Aug 24, 2016

Veeam Backup & Replication 9.0 User Guide for Microsoft Hyper-V


Veeam Backup & Replication provides a set of features for building and maintaining a flexible backup infrastructure, performing data protection tasks (such as VM backup, replication, copying backup files), and carrying out disaster recovery procedures. This article contains a high-level step by step guide of Veeam Backup & Replication, its architecture, features, data protection and disaster recovery concepts necessary to understand Veeam Backup & Replication background operations and processes.







 

Solution Architecture

Veeam Backup & Replication is a modular solution that lets you build a scalable backup infrastructure for environments of different sizes and configuration. The installation package of Veeam Backup & Replication includes a set of components that you can use to configure the backup infrastructure. Some components are mandatory and provide core functionality; some components are optional and can be installed to provide additional functionality for your business and deployment needs. 

You can co-install Veeam Backup & Replication components on the same machine, physical or virtual, or you can set them up separately for a more scalable approach.

 

Components

The Veeam backup infrastructure comprises a set of components. Some components can be deployed with the help of the setup file. Other components can be deployed via the Veeam Backup & Replication console.

 

Backup Server

The backup server is a Windows-based physical or virtual machine on which Veeam Backup & Replication is installed. It is the core component in the backup infrastructure that fills the role of the “configuration and control center”. The backup server performs all types of administrative activities:
  • Coordinates backup, replication, recovery verification and restore tasks
  • Controls job scheduling and resource allocation
  • Is used to set up and manage backup infrastructure components as well as specify global settings for the backup infrastructure
    In addition to its primary functions, a newly deployed backup server also performs the role of the default backup repository, storing backups locally.

    The backup server uses the following services and components:
    • Veeam Backup Service is a Windows service that coordinates all operations performed by Veeam Backup & Replication such as backup, replication, recovery verification and restore tasks. The Veeam Backup Service runs under the Local System account or account that has the Local Administrator permissions on the backup server.
    • Veeam Backup & Replication Console provides the application user interface and allows user access to the application's functionality.
    • Veeam Guest Catalog Service is a Windows service that manages guest OS file system indexing for VMs and replicates system index data files to enable search through guest OS files. Index data is stored in the Veeam Backup Catalog — a folder on the backup server. The Veeam Guest Catalog Service running on the backup server works in conjunction with search components installed on Veeam Backup Enterprise Manager and (optionally) a dedicated Microsoft Search Server.
    • Veeam Backup & Replication Configuration Database is used to store data about the backup infrastructure, jobs, sessions and so on. The database instance can be located on a SQL Server installed either locally (on the same machine where the backup server is running) or remotely.
    • Veeam Backup PowerShell Snap-In is an extension for Microsoft Windows PowerShell 2.0. Veeam Backup PowerShell adds a set of cmdlets to allow users to perform backup, replication and recovery tasks through the command-line interface of PowerShell or run custom scripts to fully automate operation of Veeam Backup & Replication.
    • Mount server is a component required for browsing the VM guest file system and restoring VM guest OS files and application items to the original location.

Backup & Replication Console

The Veeam Backup & Replication console is a separate client-side component that provides access to the backup server. The console is installed locally on the backup server by default. You can also use it in a standalone mode — install the console on a dedicated machine and access Veeam Backup & Replication remotely over the network. The console lets you log in to Veeam Backup & Replication and perform all kind of data protection and disaster recovery operations as if you work on the backup server.

To log in to Veeam Backup & Replication via the console, the user must be added to the Local Users group on the backup server or a group of domain users who have access to the backup server. The user can perform the scope of operations permitted by his or her role in Veeam Backup & Replication.

You can install as many remote consoles as you need so that multiple users can access Veeam Backup & Replication simultaneously. Veeam Backup & Replication prevents concurrent modifications on the backup server. If several users are working with Veeam Backup & Replication at the same time, the user who saves the changes first has the priority. Other users will be prompted to reload the wizard or window to get the most recent information about the changes in the configuration database.

If you have multiple backup servers in the infrastructure, you can connect to any of them from the same console. For convenience, you can save several shortcuts for these connections.

To make users' work as uninterrupted as possible, the remote console maintains the session for 5 minutes if the connection is lost. If the connection is re-established within this period, you can continue working without re-logging to the console.

When you install a remote console on a machine, Veeam Backup & Replication installs the following components:
  • Veeam Backup PowerShell Snap-In
  • Veeam Explorer for Microsoft Active Directory
  • Veeam Explorer for Microsoft Exchange
  • Veeam Explorer for Oracle
  • Veeam Explorer for Microsoft SQL
  • Veeam Explorer for Microsoft SharePoint
  • Mount server
The console does not have a direct access to the backup infrastructure components and configuration database. Such data as user credentials, passwords, roles and permissions are stored on the backup server side. To access this data, the console needs to connect to the backup server and query this information periodically during the work session. 

Backup & Replication Console
Requirements and Limitations for Remote Console

The machine on which you install the Veeam Backup & Replication console must meet the following requirements:
  • The remote console can be installed on a Microsoft Windows machine (physical or virtual).
  • If you install the console remotely, you can deploy it outside NAT. However, the backup server must be behind NAT. The opposite type of deployment is not supported: if the backup server is deployed outside NAT and the remote console is deployed behind NAT, you will not be able to connect to the backup server.
The Veeam Backup & Replication console has the following limitations:
  • You cannot perform restore from the configuration backup via the remote console.
  • The machines on which the remote console is installed are not added to the list of managed servers automatically. For this reason, you cannot perform some operations, for example, import backup files that reside on the remote console machine or assign roles of backup infrastructure components to this machine. To perform these operations, you must add the remote console machine as a managed server to Veeam Backup & Replication.

 

Off-Host Backup Proxy

By default, when you perform backup and replication jobs in the Hyper-V environment, VM data is processed directly on the source Hyper-V host where VMs reside, and then moved to the target, bypassing the backup server.

VM data processing can produce unwanted overhead on the production Hyper-V host and impact performance of VMs running on this host. To take data processing off the production Hyper-V host, you can use the off-host backup mode.

The off-host mode shifts the backup and replication load to a dedicated machine — an off-host backup proxy. The off-host backup proxy functions as a “data mover” which retrieves VM data from the source datastore, processes it and transfers to the destination.

The machine performing the role of an off-host backup proxy must meet the following requirements:
  • The role of an off-host backup proxy can be assigned only to a physical Microsoft Windows 2008 Server R2 machine with the Hyper-V role enabled, Windows Server 2012 machine with the Hyper-V role enabled or Windows Server 2012 R2 machine with the Hyper-V role enabled.
For evaluation and testing purposes, you can assign the off-host backup proxy role to a VM. To do this, you must enable the Hyper-V role on this VM (use nested virtualization). However, it is not recommended that you use such off-host backup proxies in the production environment.
  • The off-host backup proxy must have access to the shared storage where VMs to be backed up, replicated or copied are hosted.
  • To create and manage volume shadow copies on the shared storage, you must install a VSS hardware provider that supports transportable shadow copies on the off-host proxy and the Hyper-V host. The VSS hardware provider is usually distributed as a part of client components supplied by the storage vendor.

When you assign the role of an off-host backup proxy to the selected machine, Veeam Backup & Replication automatically installs on it light-weight components and services required for backup proxy functioning. Unlike the backup server, backup proxies do not require a dedicated SQL database — all settings are stored centrally, within the configuration database used by Veeam Backup & Replication.

To enable a Hyper-V host or a Windows machine to act as an off-host backup proxy,

Veeam Backup & Replication installs the following services on it:
  • Veeam Installer Service is an auxiliary service that is installed and started on any Windows (or Hyper-V) server once it is added to the list of managed servers in the Veeam Backup & Replication console. This service analyzes the system, installs and upgrades necessary components and services.
  • Veeam Transport is responsible for deploying and coordinating executable modules that act as "data movers" and perform main job activities on behalf of Veeam Backup & Replication, such as performing data deduplication, compression and so on.
  • Veeam Hyper-V Integration Service is responsible for communicating with the VSS framework during backup, replication and other jobs, and performing recovery tasks. The service also deploys a driver that handles changed block tracking for Hyper-V.

Guest Interaction Proxy

To interact with the VM guest OS during the backup or replication job, Veeam Backup & Replication needs to deploy a runtime process in each VM. Guest OS interaction is performed if you enable the following options in the job:
  • Application-aware processing
  • Guest file system indexing
  • Transaction logs processing
Previously, the runtime process on all VMs was deployed by the backup server. This could cause the following problems:
  • The load on the backup server was high.
  • If a connection between two sites was slow, the job performance decreased.
  • If the backup server had no network connection to VMs, application-aware processing tasks were not accomplished for these VMs.
Guest Interaction Proxy

Starting from Veeam Backup & Replication 9.0, the task of deploying the runtime process in a Microsoft Windows VM is performed by the guest interaction proxy. The guest interaction proxy is a backup infrastructure component that sits between the backup server and processed VM. The guest interaction proxy deploys the runtime process in the VM and sends commands from the backup server to the VM.

The guest interaction proxy allows you to communicate with the VM guest OS even if the backup server and processed VM run in different networks. As the task of runtime process deployment is assigned to the guest interaction proxy, the backup server only has to coordinate job activities.

Guest Interaction Proxy Important!
The guest interaction proxy deploys the runtime process only in Microsoft Windows VMs. In VMs with another guest OS, the runtime process is deployed by the backup server.

Guest Interaction Proxy

You can use multiple guest interaction proxies to improve performance. Multiple guest interaction proxies will deploy runtime processes in VMs faster compared to the same operation performed by one guest interaction proxy.

In a backup infrastructure with multiple remote sites, you can deploy a guest interaction proxy in each site. This can reduce load on the backup server and produce less traffic between the backup server and remote site. The backup server will only have to send commands to the guest interaction proxies.

Requirements for Guest Interaction Proxy
To perform the role of guest interaction proxy, the machine must meet the following requirements:
  • It must be a Microsoft Windows machine (physical or virtual).
  • You must add it to the Veeam Backup & Replication console as a managed server.
  • It must have a LAN connection to the VM that will be backed up or replicated.
The guest interaction proxy role can be performed by any machine that meets the requirements, including backup proxy, backup repository, WAN accelerator, Microsoft Hyper-V host or backup server.
Guest Interaction Proxy Note:
The guest interaction proxy functionality is available in the Enterprise and Enterprise Plus Editions of Veeam Backup & Replication.

Guest Interaction Proxy Selection
When you add a Microsoft Windows machine to the backup infrastructure, Veeam Backup & Replication deploys the Data Mover Service on it. The Data Mover Service includes the components responsible for runtime process deployment during guest OS interaction.

To assign a guest interaction proxy for the job, you must select a Microsoft Windows machine that will perform the role of the guest interaction proxy at the Guest Processing step of the backup or replication job wizard. You can assign the guest interaction proxy manually, or let Veeam Backup & Replication do it automatically. Veeam Backup & Replication uses the following priority rules to select the guest interaction proxy:
  1. A machine in the same network as the protected VM that does not perform the backup server role.
  2. A machine in the same network as the protected VM that performs the backup server role.
  3. A machine in another network that does not perform the backup server role.
  4. A machine in another network that performs the backup server role.
If Veeam Backup & Replication finds several available machines of equal priority, it selects the less loaded machine. The load is defined by the number of tasks that the machine already performs.

Guest Interaction Proxy 
Failover from Guest Interaction Proxy to Backup Server

If the guest interaction proxy fails to connect to a Microsoft Windows VM, the guest interaction proxy will not be able to access the VM and deploy a runtime process in it. In this case, the backup server will take over the role of guest interaction proxy and deploy the runtime process in the VM.

 

Backup Repository

A backup repository is a storage location where you can keep backup files and metadata for replicated VMs. You can configure the following types of backup repositories in the backup infrastructure: 

Simple Backup Repository

A backup repository is a location used by Veeam Backup & Replication jobs to store backup files. 

Technically, a backup repository is a folder on the backup storage. By assigning different repositories to jobs and limiting the number of parallel jobs for each one, you can balance the load across your backup infrastructure.

In the Veeam backup infrastructure, you can use one of the following repository types:
  • Microsoft Windows server with local or directly attached storage. The storage can be a local disk, directly attached disk-based storage (such as a USB hard drive), or iSCSI/FC SAN LUN in case the server is connected into the SAN fabric.
    On a Windows repository, Veeam Backup & Replication deploys a local Veeam Data Mover Service (when you add a Windows-based server to the product console, Veeam Backup & Replication installs a set of components including the Veeam Data Mover Service on that server). When any job addresses the backup repository, the Veeam Data Mover Service on the backup repository establishes a connection with the source-side Veeam Data Mover Service on the backup proxy, enabling efficient data transfer over LAN or WAN.
  • Linux server with local, directly attached storage or mounted NFS. The storage can be a local disk, directly attached disk-based storage (such as a USB hard drive), NFS share, or iSCSI/FC SAN LUN in case the server is connected into the SAN fabric.
When any task addresses a Linux repository, Veeam Backup & Replication deploys and starts the Veeam Data Mover Service on the backup repository. The Data Mover Service establishes a connection with the source-side Data Mover Service on the backup proxy, enabling efficient data transfer over LAN or WAN.
  • CIFS (SMB) share. SMB share cannot host Veeam Data Mover Services. For this reason, data to the SMB share is written from the gateway server. By default, this role performs an on-host or off-host backup proxy that is used by the job for data transport.
However, if you plan to move VM data to an offsite SMB repository over a WAN link, it is recommended that you deploy an additional gateway server in the remote site, closer to the SMB repository.

Veeam Backup & Replication will deploy a Veeam Data Mover Service on this gateway server, which will improve data transfer performance.
  • Deduplicating storage appliance. Veeam Backup & Replication supports the following deduplicating storage appliances:
  • EMC Data Domain
  • ExaGrid
  • HPE StoreOnce

Scale-Out Backup Repository

You can configure a scale-out backup repository in the backup infrastructure.

The scale-out backup repository is a logical entity. It groups several simple backup repositories, or extents. When you configure the scale-out backup repository, you actually create a pool of storage devices and systems, summarizing their capacity.

You can expand the scale-out backup repository at any moment. For example, if backup data grows and the backup repository reaches the storage limit, you can add a new storage system to the scale-out backup repository. The free space on this storage system will be added to the capacity of the scale-out backup repository. As a result, you will not have to move backups to a backup repository of a larger size.

To deploy a scale-out backup repository, you must configure a number of simple backup repositories and include them into the scale-out backup repository as extents. You can mix backup repositories of different types in one scale-out backup repository:
  • Microsoft Windows backup repositories
  • Linux backup repositories
  • Shared folders
  • Deduplicating storage appliances
For example, you can add a Microsoft Windows server and deduplicating storage appliance to the same scale-out backup repository.

You can use the scale-out backup repository for the following types of jobs and tasks:
  • Backup jobs.
  • Backup copy jobs. You can copy backups that reside on scale-out backup repositories and store backup copies on scale-out backup repositories.
  • VeeamZIP tasks.
Backup files stored on the scale-out repository can be used for all types of restores, replication from backup and backup copy jobs. You can verify such backups with SureBackup jobs. The scale-out backup repository can be used as a staging backup repository for restore from tape media. Files restored from the tape media are placed to the extents according to data placement policy configured for the scale-out backup repository.

Limitations for Scale-out Backup Repositories

The scale-out backup repository has the following limitations:
  • The scale-out backup repository functionality is available only in Enterprise and Enterprise Plus editions of Veeam Backup & Replication.
If you configure a scale-out backup repository and then downgrade to the Standard license, you will not be able to run jobs targeted at the scale-out backup repository. However, you will be able to perform restore from the scale-out backup repository.
  • You cannot use the scale-out backup repository as a target for the following types of jobs:
  • Configuration backup job
  • Replication jobs
  • Endpoint backup jobs
  • You cannot add a backup repository as an extent to the scale-out backup repository if any job of unsupported type is targeted at this backup repository or if the backup repository contains data produced by jobs of unsupported types (for example, replica metadata). To add such backup repository as an extent, you must first target unsupported jobs to another backup repository and remove the job data from the backup repository.
  • You cannot use a scale-out backup repository as a cloud repository. You cannot add a cloud repository as an extent to the scale-out backup repository.
  • You cannot use a backup repository with rotated drives as an extent to a scale-out backup repository. Even you enable the This repository is backed up by rotated hard drives setting for an extent, Veeam Backup & Replication will ignore this setting and use an extent as a simple backup repository.
  • If a backup repository is added as an extent to the scale-out backup repository, you cannot use it as a regular backup repository.
  • You cannot add a scale-out backup repository as an extent to another scale-out backup repository.
  • You cannot add a backup repository as an extent if this backup repository is already added as an extent to another scale-out backup repository.
  • You cannot add a backup repository on which some activity is being performed (for example, a backup job or restore task) as an extent to the scale-out backup repository.
  • If you use Enterprise Edition of Veeam Backup & Replication, you can create 1 scale-out backup repository with 3 extents for this scale-out backup repository. Enterprise Plus Edition has no limitations on the number of scale-out backup repositories or extents.

 

Extents

The scale-out backup repository can comprise one or more extents. The extent is a standard backup repository configured in the backup infrastructure. You can add any simple backup repository, except the cloud repository, as an extent to the scale-out backup repository.

The backup repository added to the scale-out backup repository ceases to exist as a simple backup repository. You cannot target jobs to this backup repository. Instead, you have to target jobs at the configured scale-out backup repository.

On every extent, Veeam Backup & Replication creates the definition.erm file. This file contains a description of the scale-out backup repository and information about its extents. 

Extents inherit most configuration settings from the underlying backup repositories. The following settings are inherited:
  • Number of tasks that can be performed simultaneously
  • Read and write data rate limit
  • Data decompression settings
  • Block alignment settings
The following settings are not inherited:
  • Rotated drive settings. Rotated drive settings are ignored and cannot be configured at the level of the scale-out backup repository.
  • Per-VM backup file settings. Per-VM settings can be configured at the level of the scale-out backup repository.
Limitations, specific for certain types of backup repositories, apply to extents. For example, if you add EMC Data Domain as an extent to the scale-out backup repository, you will not be able to create a backup chain longer than 60 points on this scale-out backup repository.

Extents of the scale-out backup repository should be located in the same site. Technically, you can add extents that reside in different sites to the scale-out backup repository. However, in this case Veeam Backup & Replication will have to access VM backup files on storage devices in different locations, and the backup performance will degrade.

 

Backup File Placement

Veeam Backup & Replication stores backup files on all extents of the scale-out backup repository.

When you configure a scale-out backup repository, you must set the backup file placement policy for it. The backup file placement policy describes how backup files are distributed between extents. You can choose one of two policies:
  • Data locality — all backup files that belong to the same backup chain are stored on the same extent of the scale-out backup repository.
The Data locality policy does not put any limitations to backup chains. A new backup chain may be stored on the same extent or another extent. For example, if you create an active full backup, Veeam Backup & Replication may store the full backup file to another extent, and all dependent incremental backup files will be stored together with this full backup file. 

However, if you use a deduplicating storage appliance as an extent to the scale-out backup repository, Veeam Backup & Replication will attempt to place a new full backup to the extent where the full backup from the previous backup chain resides. Such behavior will help increase the data deduplication ratio.
  • Performance — full backup files and incremental backup files that belong to the same backup chain are stored on different extents of the scale-out backup repository. If necessary, you can explicitly specify on which extents full backup files and incremental backup files must be stored.
The Performance policy can improve performance of transform operations if you use raw data devices as extents. When Veeam Backup & Replication performs transform operations, it needs to access a number of backup files in the backup repository. If these files are located on different storages, the I/O load on the storages hosting backup files will be lower.

If you set the Performance policy, you must make sure that the network connection between extents is fast and reliable. You must also make sure all extents are online when the backup job, backup copy job or a restore task starts. If any extent hosting backup files in the current backup chain is not available, the backup chain will be broken, and Veeam Backup & Replication will not be able to complete the task. To avoid data loss in this situation, you can enable the Perform full backup when required extent is offline option for the scale-out backup repository. With this option enabled, Veeam Backup & Replication will create a full backup instead of incremental backup if some files are missing from the backup chain.

The backup file placement policy is not strict. If the necessary extent is not accessible, Veeam Backup & Replication will disregard the policy limitations and attempt to place the backup file to the extent that has enough free space for the backup file.

For example, you have set the Performance policy for the scale-out backup repository and specified that full backup files must be stored on Extent 1 and incremental backup files must be stored on Extent 2. If before an incremental backup job session Extent 2 goes offline, the new incremental backup file will be placed to Extent 1.

Extent Selection
To select an extent for backup file placement, Veeam Backup & Replication checks the following conditions:
  1. Availability of extents on which backup files reside. If some extent with backup files from the current backup chain is not accessible, Veeam Backup & Replication will trigger a full backup instead of incremental (if this option is enabled).
  2. Backup placement policy set for the scale-out backup repository.
  3. Load control settings — maximum number of tasks that the extent can process simultaneously.
  4. Amount of free space available on the extent — the backup file is placed to the extent with the most amount of free space.
  5. Availability of files from the current backup chain — extents that host incremental backup files from the current backup chain (or current VM) have a higher priority than extents that do not host such files.
At the beginning of the job session, Veeam Backup & Replication estimates how much space the backup file requires and checks the amount of free space on extents. Veeam Backup & Replication assumes that the following amount of space is required for backup files:
  • For per-VM backup chains: the size of the full backup file is equal to 50% of source VM data. The size of an incremental backup file is equal to 10% of source VM data.
This mechanism is also applied to backup files created with backup copy jobs.
  • For single file backup chains: the size of the full backup file is equal to 50% of source data for all VMs in the job. For the first incremental job session, the size of an incremental backup file is equal to 10% the full backup file. For subsequent incremental job sessions, the size of an incremental backup file is equal to 100% of the previous incremental backup file.
Extent Selection for Backup Repositories with Performance Policy

If you set the Performance policy for the scale-out backup repository, Veeam Backup & Replication always stores full backup files and incremental backup files that belong to the same backup chain on different extents. To choose the extent to which a backup file can be stored, Veeam Backup & Replication applies this policy and policies mentioned above.

For example, a scale-out backup repository has 2 extents that have 100 GB and 200 GB of free space. You set the Performance policy for the scale-out backup repository and define that all types of backup files (full and incremental) can be placed on both extents.

When a backup job runs, Veeam Backup & Replication picks the target extent in the following manner:
  1. During the first job session, Veeam Backup & Replication checks to which extent a full backup file can be stored. As both extents can host the full backup file, Veeam Backup & Replication checks which extent has more free space, and picks the extent that has 200 GB of free space.
  2. During incremental job session, Veeam Backup & Replication checks to which extent an incremental backup file can be stored. As both extents can host the incremental backup file, Veeam Backup & Replication picks the extent that does not store the full backup file — the extent that has 100 GB of free space.

 

Service Actions with Scale-Out Backup Repositories

You can perform service actions with extents of scale-out backup repositories:
  • Put extents to the Maintenance mode
  • Evacuate backups from extents

 

Maintenance Mode

In some cases, you may want to perform service actions with extents of the scale-out backup repository. For example, you need to upgrade the backup repository server and add more memory to it. Or you want to replace a storage device backing the extent and need to relocate backup files. Before you start service actions, you must put the extent to the Maintenance mode.

An extent in the Maintenance mode operates with the limited functionality:
  • Veeam Backup & Replication does not start new tasks targeted at this extent.
  • You cannot restore VM data from backup files residing on the extent. You also cannot restore VM data from backup files residing on other extents if a part of the backup chain resides on the extent in the Maintenance mode.
When you switch the Maintenance mode, Veeam Backup & Replication launches the Repository Maintenance job. The Repository Maintenance job checks the status of jobs and tasks targeted at the extent and puts the extent to one of the following modes:
  • If no tasks using the extent are currently running, the job puts the extent to the Maintenance mode immediately.
  • If the extent is busy with any task, for example, a backup job, the job puts the extent to the Maintenance pending state and waits for the task to complete. When the task is complete, the extent is put to the Maintenance mode.

 

Backup Files Evacuation

If you want to exclude an extent from the scale-out backup repository, you first need to evacuate backup files from this extent. When you evacuate backups, Veeam Backup & Replication moves backup files from the extent to other extents that belong to the same scale-out backup repository. As a result, the backup chains remain consistent and you can work with them in a usual way.

The extent must be put to the Maintenance mode before you evacuate backups from it. If the extent is in the normal operational mode, the Evacuate option will not be available for this extent.

When selecting the target extent for evacuated files, Veeam Backup & Replication attempts to keep to the backup placement settings specified for remaining extents. For example, you have 3 extents in the scale-out backup repository with the following backup file placement settings:
  • On Extent 1, full backup files are stored.
  • On Extent 2 and Extent 3, incremental backup files are stored.
If you evacuate backup files from Extent 2, Veeam Backup & Replication will relocate them to Extent 3.

Backup Repositories with Rotated Drives

You can configure a backup repository to use rotated drives. This scenario can be helpful if you want to store backups on several external hard drives (for example, USB or eSATA) and plan to regularly swap these drives between different locations.

To use rotated drives, you must enable the This repository is backed up by rotated hard drives option in the advanced settings of the backup repository. When this option is enabled, Veeam Backup & Replication recognizes the backup target as a backup repository with rotated drives and uses a specific algorithm to make sure that the backup chain created on these drives is not broken.

Microsoft Windows Backup Repository
A job targeted at a backup repository with rotated drives is performed in the following way:
  1. Veeam Backup & Replication creates a regular backup chain on the currently attached drive.
  2. When a new job session starts, Veeam Backup & Replication checks if the backup chain on the currently attached drive is consistent. The consistent backup chain must contain a full backup and all incremental backups that have been produced by the job. This requirement applies to all types of backup chains: forever forward incremental, forward incremental and reverse incremental.
If external drives have been swapped, and the full backup or any incremental backups are missing from the currently attached drive, Veeam Backup & Replication behaves in the following way:
  • [For backup jobs] Veeam Backup & Replication starts the backup chain anew. It creates a new full backup file on the drive, and this full backup is used as a starting point for subsequent incremental backups.
  • [For backup copy jobs] If the attached drive is empty, Veeam Backup & Replication creates a full backup on it. If there is a backup chain on the drive, Veeam Backup & Replication creates a new incremental backup and adds it to the backup chain. The latest incremental backup existing in the backup chain is used as a starting point for the new incremental backup.
  1. [For external drives attached to Microsoft Windows servers] Veeam Backup & Replication checks the retention policy set for the job. If some backup files in the backup chain are outdated, Veeam Backup & Replication removes them from the backup chain.
  2. When you swap drives again, Veeam Backup & Replication behaves in the following way:
  • [For backup jobs] Veeam Backup & Replication checks the backup chain for consistency and creates a new full backup.
  • [For backup copy jobs] If the attached drive is empty, Veeam Backup & Replication creates a full backup on it. If there is a backup chain on the drive, Veeam Backup & Replication creates a new incremental backup and adds it to the backup chain. The latest incremental backup existing in the backup chain is used as a starting point for the new incremental backup.
When you specify retention settings for a job targeted at a backup repository with rotated drives, you must define the total number of restore points that you want to retain on all drives in the set. For example, if you set retention to 14, the job will keep the total of 14 restore points across all drives.

Backup Repositories with Rotated Drives
Drive letters for external drives may change when you add new volumes or storage hardware such as CD-ROM on the server. On Microsoft Windows backup repositories, Veeam Backup & Replication can keep track of drives and detect them even if the drive letter changes.

To detect a drive correctly, Veeam Backup & Replication must have a record about it in the configuration database. Consider the following requirements:
  • When you insert a drive for the first time, the drive is not registered in the configuration database. Such drive must have the same letter as the one specified in the Path to folder field in the backup repository settings.
If the drive has some other letter, Veeam Backup & Replication will not be able to detect and use it.
  • When you insert a drive that has already been used and has some restore points on it, the drive is already registered in the configuration database. Veeam Backup & Replication will be able to detect and use it, even if the drive letter changes.






Linux and Shared Folder Backup Repository
If you use a Linux server or CIFS share as a backup repository with rotated drives, Veeam Backup & Replication employs a “cropped” mechanism of work with rotated drives.

Veeam Backup & Replication keeps information only about the latest backup chain in the configuration database. Information about previous backup chains is removed from the database. For this reason, the retention policy set for the job may not work as expected.

A job targeted at a backup repository with rotated drives is performed in the following way:
  1. During the first run of the job, Veeam Backup & Replication creates a regular backup full backup on the drive that is attached to the backup repository server.
  2. During the next job session, Veeam Backup & Replication checks if the current backup chain on the attached drive is consistent. The consistent backup chain must contain a full backup and all incremental backups subsequent to it. This requirement applies to all types of backup chains: forever forward incremental, forward incremental and reverse incremental.
  • If the current backup chain is consistent, Veeam Backup & Replication adds a new restore point to the backup chain.
  • If external drives have been swapped, and the current backup chain is not consistent,  
  • Veeam Backup & Replication always starts a new backup chain (even if restore points from previous backup chains are available on the attached drive). Veeam Backup & Replication creates a new full backup file on the drive, and this full backup is used as a starting point for subsequent incremental backups.

    As soon as Veeam Backup & Replication starts a new backup chain on the drive, it removes information about restore points from previous backup chains from the configuration database. Backup files corresponding to these previous restore points are not deleted, they remain on disk. This happens because Veeam Backup & Replication applies the retention policy only to the current backup chain, not to previous backup chains.
Backup Repositories with Rotated Drives
Limitations for Backup Repositories with Rotated Drives
Backup repositories with rotated drives have the following limitations:
  1. You cannot store archive full backups (GFS backups) created with backup copy jobs in backup repositories with rotated drives.
  2. You cannot store per-VM backup files in backup repositories with rotated drives.

 

Support for Deduplicating Storage Systems

For disk-to-disk backups, you can use a deduplicating storage system as a target.

Veeam Backup & Replication supports the following deduplicating storage appliances:
  • EMC Data Domain
  • ExaGrid
  • HPE StoreOnce

 

EMC Data Domain

You can use EMC Data Domain storage systems with Data Domain Boost (DD Boost) as backup repositories.

The DD Boost technology offers a set of features for advanced data processing:
  • Distributed Segment Processing
  • Advanced Load Balancing and Link Failover
  • Virtual Synthetics
  • Managed File Replication
Veeam Backup & Replication supports Distributed Segment Processing, Advanced Load Balancing, Link Failover and Virtual Synthetics. Managed File Replication is not supported.

In addition to these technologies, Veeam Backup & Replication supports in-flight data encryption and per storage unit streams.

Distributed Segment Processing
Distributed Segment Processing lets EMC Data Domain “distribute” the deduplication process and perform a part of data deduplication operations on the backup proxy side.

Without Distributed Segment Processing, EMC Data Domain performs deduplication on the EMC Data Domain storage system. The backup proxy sends unfiltered data blocks to EMC Data Domain over the network. Data segmentation, filtering and compression operations are performed on the target side, before data is written to disk.

With Distributed Segment Processing, operations on data segmentation, filtering and compression are performed on the backup proxy side. The backup proxy sends only unique data blocks to EMC Data Domain. As a result, the load on the network reduces and the network throughput improves.

Advanced Load Balancing and Link Failover
Advanced Load Balancing and Link Failover allow you to balance data transfer load and route VM data traffic to a working link in case of network outage problems.

Without Advanced Load Balancing, every backup server connects to Data Domain on a dedicated Ethernet link. Such configuration does not provide an ability to balance the data transfer load across the links. If a network error occurs during the data transfer process, the backup job fails and needs to be restarted.

Advanced Load Balancing allows you to aggregate several Ethernet links into one interface group. As a result, EMC Data Domain automatically balances the traffic load coming from several backup servers united in one group. If some link in the group goes down, EMC Data Domain automatically performs link failover, and the backup traffic is routed to a working link.

Virtual Synthetics
Veeam Backup & Replication supports Virtual Synthetic Fulls by EMC Data Domain. Virtual Synthetic Fulls let you synthesize a full backup on the target backup storage without physically copying data from source volumes. To construct a full backup file, EMC Data Domain uses pointers to existing data segments on the target backup storage. Virtual Synthetic Fulls reduce the workload on the network and backup infrastructure components and increase the backup job performance.

In-Flight Data Encryption
Veeam Backup & Replication supports in-flight encryption introduced in EMC Data Domain Boost 3.0. If necessary, you can enable data encryption at the backup repository level. Veeam Backup & Replication will leverage the EMC Data Domain technology to encrypt data transported between the EMC DD Boost library and EMC Data Domain system.

Per Storage Unit Streams
Veeam Backup & Replication supports per storage unit streams on EMC Data Domain. The maximum number of parallel tasks that can be targeted at the backup repository (the Limit maximum concurrent tasks to N setting) is applied to the storage unit, not the whole EMC Data Domain system.

 

How EMC Data Domain Works

To support the EMC DD Boost technology, Veeam Backup & Replication leverages two EMC Data Domain components:
  • DD Boost library. The DD Boost library is a component of the EMC Data Domain system. The DD Boost library is embedded into the Veeam Data Mover Service setup. When you add a Microsoft Windows server to the backup infrastructure, the DD Boost Library is automatically installed on the added server together with the Data Mover Service.
  • DD Boost server. The DD Boost server is a target-side component running on the OS of the EMC Data Domain storage system.
To communicate with EMC Data Domain, Veeam Backup & Replication uses the DD Boost library deployed on a gateway server. The gateway server is a backup infrastructure component that “bridges” the backup server and EMC Data Domain storage system. The gateway server must meet the following requirements:
  • The server must run Microsoft Windows OS.
  • The server must be added to the backup infrastructure.
  • The server must have access to the backup server and EMC Data Domain appliance.
You define what gateway server to use when you assign a backup repository role to EMC Data Domain. You can define the gateway server explicitly or instruct Veeam Backup & Replication to select it automatically.

For EMC Data Domain storage systems working over Fibre Channel, you must explicitly define the gateway server that will communicate with EMC Data Domain. As a gateway server, you must use a Microsoft Windows server that is added to the backup infrastructure and has access to EMC Data Domain over Fibre Channel.

How EMC Data Domain Works

 

Supported Protocols

Veeam Backup & Replication supports EMC Data Domain storage systems working over the following protocols:
  • TCP/IP protocol: Veeam Backup & Replication communicates with the EMC Data Domain server by sending commands over the network.
  • Fibre Channel protocol: Veeam Backup & Replication communicates with the EMC Data Domain Fibre Channel server by sending SCSI commands over Fibre Channel.

 

Limitations for EMC Data Domain

If you plan to use EMC Data Domain as a backup repository, mind the following limitations:
  • Use of EMC Data Domain with DD Boost does not guarantee improvement of job performance; it reduces the load on the network and improves the network throughput.
  • EMC Data Domain requires at least 1 Gbps network and 0% of packets data loss between the gateway server and EMC Data Domain storage appliance. In the opposite case, stable work of EMC Data Domain cannot be guaranteed.
  • EMC Data Domain does not support the reverse incremental backup method. Do not enable this option for backup jobs targeted at this type of backup repository.
  • When you create a backup job targeted at EMC Data Domain, Veeam Backup & Replication will offer you to switch to optimized job settings and use the 4 MB size of data block for VM data processing. It is recommended that you use optimized job settings. Large data blocks produce a smaller metadata table that requires less memory and CPU resources to process.
  • The length of forward incremental and forever forward incremental backup chains (chains that contain one full backup and a set of subsequent incremental backups) cannot be greater than 60 restore points. To overcome this limitation, schedule full backups (active or synthetic) to split the backup chain into shorter series. For example, to perform backups at 30-minute intervals 24 hours a day, you must schedule synthetic fulls every day. In this scenario, intervals immediately after midnight may be skipped due to duration of synthetic processing.
  • If you connect to EMC Data Domain over Fibre Channel, you must explicitly define a gateway server to communicate with EMC Data Domain. As a gateway server, you must use a Microsoft Windows server that is added to the backup infrastructure and has access to the EMC Data Domain storage appliance over Fibre Channel.

 

ExaGrid

You can use ExaGrid appliances as backup repositories.
ExaGrid uses post-process deduplication. Data deduplication is performed on the target storage system. After VM data is written to disk, ExaGrid analyses bytes in the newly transferred data portions. ExaGrid compares versions of data over time and stores only the differences to disk.

ExaGrid deduplicates data at the storage level. Identical data blocks are detected throughout the whole storage system, which increases the deduplication ratio.

Veeam Backup & Replication works with ExaGrid appliances as with a Linux backup repository. To communicate with ExaGrid, Veeam Backup & Replication uses two Data Mover Services that are responsible for data processing and transfer:
  • Data Mover Service on the backup proxy
  • Data Mover Service on the ExaGrid appliance


Limitations for ExaGrid
ExaGrid appliances achieve a lower deduplication ratio when a backup job uses multi-task processing. Processing a single task at a time within each backup job results in the best deduplication ratio. If you decide to use ExaGrid as a backup repository, all tasks executed within a backup job should be processed sequentially, one by one. To do this, you must limit the maximum concurrent tasks to 1 in the settings of ExaGrid backup repositories.

The ExaGrid appliance can handle many concurrent backup jobs, with one of the highest ingest rates in the market. To accomplish the maximum ingest and shortest backup time, you need to configure multiple backup jobs, each targeted at its own backup repository. Then schedule these jobs to run concurrently.

 

HPE StoreOnce

You can use HPE StoreOnce storage appliances as backup repositories. Depending on the storage configuration and type of the backup target, HPE StoreOnce can work in the following ways:
  • Perform source-side deduplication
  • Perform target-side deduplication
  • Work in the shared folder mode
Source-Side Data Deduplication
HPE StoreOnce performs source-side deduplication if the backup target meets the following requirements:
  1. You have a Catalyst license installed on HPE StoreOnce.
  2. You use a Catalyst store as a backup repository.
  3. The Catalyst store is configured to work in the Low Bandwidth mode (Primary and Secondary Transfer Policy).
  4. You add the HPE StoreOnce Catalyst as a deduplicating storage appliance, not as a shared folder to the backup infrastructure.
To deduplicate data on the source side, HPE StoreOnce uses the HPE StoreOnce Catalyst agent. The HPE StoreOnce Catalyst agent is a component of the HPE StoreOnce Catalyst software. It is installed on the gateway server communicating with the HPE StoreOnce appliance.

HPE StoreOnce deduplicates data on the source side, before writing it to target:
  1. During the backup job session, HPE StoreOnce analyzes data incoming to the HPE StoreOnce appliance in chunks and computes a hash value for every data chunk. Hash values are stored in an index on disk.
  2. The HPE StoreOnce Catalyst agent calculates hash values for data chunks in a new data flow and sends these hash values to target.
  3. HPE StoreOnce identifies which data blocks are already saved on disk and communicates this information to the HPE StoreOnce Catalyst agent. The HPE StoreOnce Catalyst agent sends only unique data blocks to target.
As a result, the load on the network reduces, the backup job performance improves, and you can save on disk space.

HPE StoreOnce
Target-Side Data Deduplication
HPE StoreOnce performs target-side deduplication if the backup target is configured in the following way:
  • For a Catalyst store:
  • The Catalyst store works in the High Bandwidth mode (Primary or Secondary Transfer Policy is set to High Bandwidth).
  • The Catalyst license is installed on the HPE StoreOnce (required).
  • The Catalyst store is added as a backup repository to the backup infrastructure.
  • For a CIFS store:
  • The Catalyst license is not required.
  • The CIFS store is added as a backup repository to the backup infrastructure.

HPE StoreOnce deduplicates data on the target side, after the data is transported to HPE StoreOnce:
  1. HPE StoreOnce analyzes data incoming to the HPE StoreOnce appliance in chunks and creates a hash value for every data chunk. Hash values are stored in an index on the target side.
  2. HPE StoreOnce analyzes VM data transported to target and replaces identical data chunks with references to data chunks that are already saved on disk.
As a result, only new data chunks are written to disk, which helps save on disk space.

HPE StoreOnce

Shared Folder Mode
If you do not have an HPE StoreOnce Catalyst license, you can add the HPE StoreOnce appliance as a shared folder backup repository. In this mode, HPE StoreOnce will perform target-side deduplication.

If you work with HPE StoreOnce in the shared folder mode, the performance of backup jobs and transform operations is lower (in comparison with the integration mode, when HPE StoreOnce is added as a deduplicating storage appliance).

How HPE StoreOnce Works

To work with HP StoreOnce, Veeam Backup & Replication leverages the HPE StoreOnce Catalyst technology and two HPE StoreOnce components:
  • HPE StoreOnce Catalyst agent. The HPE StoreOnce Catalyst agent is a component of the HPE StoreOnce Catalyst software. The HPE StoreOnce Catalyst agent is embedded into the Veeam Data Mover Service setup. When you add a Microsoft Windows server to the backup infrastructure, the HPE StoreOnce Catalyst agent is automatically installed on the added server together with the Data Mover Service.
  • HPE StoreOnce appliance. The HPE StoreOnce appliance is an HPE StoreOnce storage system on which Catalyst stores are created.
Veeam Backup & Replication uses two Data Mover Services:
  • Data Mover Service on the backup proxy
  • Data Mover Service on the gateway server
The gateway server is a backup infrastructure component that “bridges” the backup server and HPE StoreOnce appliance. The gateway server must meet the following requirements:
  • The server must run Microsoft Windows OS.
  • The server must be added to the backup infrastructure.
  • The server must have access to the backup server and HPE StoreOnce appliance.
The gateway server is selected when you assign a backup repository role to the HPE StoreOnce appliance. You can define the gateway server explicitly or instruct Veeam Backup & Replication to select it automatically.

For HPE StoreOnce storage systems working over Fibre Channel, you must explicitly define the gateway server to communicate with HPE StoreOnce. As a gateway server, you must use a Microsoft Windows server that is added to the backup infrastructure and has access to HPE StoreOnce over Fibre Channel.

How HPE StoreOnce Works Tip:
For work with HP StoreOnce, Veeam Backup & Replication uses the Catalyst agent installed on the gateway proxy. If you want to reduce the load on the network between the source and target side, assign the gateway server role to a machine on the source side, closer to the backup proxy.


How HPE StoreOnce Works

 

Limitations for HPE StoreOnce

If you plan to use HPE StoreOnce as a backup repository, mind the following limitations. Limitations apply only if you use HPE StoreOnce in the integration mode, not the shared folder mode.
  • Backup files on HPE StoreOnce are locked exclusively by a job or task. If you start several tasks at a time, Veeam Backup & Replication will perform a task with a higher priority and will skip or terminate a task with a lower priority.
In Veeam Backup & Replication, tasks have the following priority levels (starting with the top priority): backup job > backup copy > restore. For example, if the backup and backup copy jobs start simultaneously, Veeam Backup & Replication will terminate the backup copy task. If a file is locked with the backup job, you will not be able to restore VM data from this file.
  • When you create a backup job targeted at HPE StoreOnce, Veeam Backup & Replication will offer you to switch to optimized job settings and use the 4 MB size of data block for VM data processing. It is recommended that you use optimized job settings. Large data blocks produce a smaller metadata table that requires less memory and CPU resources to process.
  • The HPE StoreOnce backup repository always works in the Use per-VM backup files mode.
  • The length of backup chains (chains that contain one full backup and a set of subsequent incremental backups) on HPE StoreOnce cannot be greater than 7 restore points. The recommended backup job schedule is the following: not more than 1 incremental backup once a day, not fewer than one full backup (active or synthetic) once a week.
  • HPE StoreOnce does not support the reverse incremental backup method.
  • The HPE StoreOnce backup repository does not support the Defragment and compact full backup file option (for backup and backup copy jobs).
  • You cannot perfom quick migration for Microsoft Hyper-V VMs started with Instant VM Recovery from the backup that resides on the HP StoreOnce backup repository.
  • You cannot use the HP StoreOnce backup repository as a target for Veeam Endpoint backup jobs. Backup copy jobs, however, can be targeted at the HP StoreOnce backup repository.
  • You cannot use the HPE StoreOnce backup repository as a source or target for file copy jobs.
  • You cannot use the HPE StoreOnce backup repository as a cloud repository.
Several Backup Repositories on HPE StoreOnce
You can configure several backup repositories on one HPE StoreOnce appliance and associate them with different gateway servers.

Mind the following:
  • If you configure several backup repositories on HPE StoreOnce and add them as extents to a scale-out backup repository, make sure that all backup files from one backup chain are stored on one extent. If backup files from one backup chain are stored to different extents, the transform operations performance will be lower.
  • HPE StoreOnce has a limit on the number of opened files that applies to the whole appliance. Tasks targeted at different backup repositories on HPE StoreOnce and run in parallel will equally share this limit.
  • For HPE StoreOnce working over Fibre Channel, there is a limitation on the number of connections from one host. If you connect several backup repositories to one gateway, backup repositories will compete for connections.
  • Deduplication on HPE StoreOnce works within the limits of one object store.

 

Gateway Server

A gateway server is an auxiliary backup infrastructure component that “bridges” the backup server and backup repository. The gateway server is required if you deploy the following types of backup repositories in the backup infrastructure:
  • Shared folder backup repositories
  • EMC DataDomain and HPE StoreOnce deduplicating storage appliances
Shared folder repositories, EMC DataDomain and HPE StoreOnce cannot host Data Mover Services — Veeam components that establish a connection between a backup proxy and backup repository (in case of backup jobs) or between backup repositories (in case of backup copy jobs). To overcome this limitation, Veeam Backup & Replication uses gateway servers.

In the backup infrastructure, a gateway server hosts the Veeam Data Mover Service.

Veeam Backup & Replication establishes a connection between the source Data Mover Service and target Data Mover Service, and transports data from/to backup repositories via gateway servers.

Gateway Server
A machine performing the role of a gateway server must meet the following requirements:
  • A gateway server can run on a physical or virtual machine.
  • The gateway server can run on a Microsoft Windows machine or Microsoft Hyper-V host.
  • The machine must be added to the backup infrastructure.
  • The machine must have access to the backup repository — shared folder, EMC DataDomain or HPE StoreOnce.
To configure a gateway server, you must pass through the Add New Backup Repository wizard and select a machine that will perform the role of a gateway server. You can select a gateway server explicitly or instruct Veeam Backup & Replication to select it automatically.
  • If you select a gateway server explicitly, Veeam Backup & Replication uses the selected machine as a gateway server.
  • If you instruct Veeam Backup & Replication to select the gateway server automatically, Veeam Backup & Replication selects a gateway server using the following rules:
  • For backup jobs: the role of a gateway server is assigned to a machine performing the role of a backup proxy (onsite or offsite).
  • For backup copy jobs: if a backup copy job uses a direct data path, the role of a gateway server is assigned to the mount server associated with the backup repository (Veeam Backup & Replication fails over to the backup server if the mount server is not accessible for some reason). If a backup copy job uses WAN accelerators, the role of a gateway server is assigned to WAN accelerators. For example, if you copy backup from a source Microsoft Windows backup repository to a shared folder backup repository, the gateway server role is assigned to the target WAN accelerator. If you copy backups between 2 shared folder backup repositories, the gateway server role is assigned to the source and target WAN accelerators.
  • For backup to tape jobs: the role of a gateway server is assigned to the backup server.
In the common case, a machine to which you assign the role of a gateway server must be located as close to the backup repository as possible. However, if you use a deduplicating storage appliance with source-side data deduplication, it is reasonable to assign the role of a gateway server to a machine that is located closer to the backup proxy. This will help you reduce the amount of traffic travelling over the network.

Veeam Backup & Replication may use one or several gateway servers to process VMs in the job. The number of gateway servers depends on backup repository settings. If the Use per-VM backup files option is disabled, Veeam Backup & Replication selects one gateway server for the whole backup repository. If the Use per-VM backup files option is enabled, Veeam Backup & Replication selects a gateway server per every VM in the job. The rules of gateway server selection are described above.

For example, a backup job processes 2 VMs. The job is targeted at a backup repository for which the Use per-VM backup files option is enabled. In this case, Veeam Backup & Replication will detect which backup proxies were used to process VMs in the job. If VMs were processed with 2 different backup proxies, Veeam Backup & Replication will assign the role of gateway servers to these backup proxies. If VMs were processed with the same backup proxy, Veeam Backup & Replication will assign the role of a gateway server to this backup proxy, and will use it for both VMs in the job.

For scale-out backup repositories, Veeam Backup & Replication uses one gateway server per every extent. The rules of gateway server selection are described above.

Limitations for Gateway Servers
For deduplicating storage appliances working over Fibre Channel, you must explicitly select a gateway server that will communicate with the appliance. As a gateway server, you must use a Microsoft Windows server that is added to the backup infrastructure and has access to the appliance over Fibre Channel.

 

Mount Server

The mount server is required if you perform restore VM guest OS files and application items to the original location. The mount server lets you route VM traffic by an optimal way, reduce load on the network and speed up the restore process.

When you perform file-level restore or application item restore, Veeam Backup & Replication needs to mount the content of the backup file to a staging server. The staging server must be located in the same site as the backup repository where backup files are stored. If the staging server is located in some other site, Veeam Backup & Replication may route data traffic in a non-optimal way.

For example, if the backup server is located in the local site while the source host and backup repository are located in the remote site, during restore to original location Veeam Backup & Replication will route data traffic in the following way:
  1. From the remote site to the local site — to mount the content of the backup file to the staging server.
  2. From the local site to the remote site — to restore files or application items.
Mount Server
To prevent VM data from traveling between sites, Veeam Backup & Replication uses the mount server. The mount server acts as a "mount point" for backups in the backup repository. When you restore files or application items to the original location, Veeam Backup & Replication mounts the content of the backup file to the mount server (or the original VM for restore to the Microsoft SQL Server and Oracle VMs) and copies files or items to their destination via this mount server or VM.

The mount server is created for every backup repository and associated with it. When you configure a backup repository, you define which server you want to use as a mount server for this backup repository. By default, Veeam Backup & Replication assigns the mount server role to the following machines:
  • Backup repository. For Microsoft Windows backup repositories, the mount server role is assigned to the backup repository server itself.
  • Backup server. For Linux, shared folder backup repositories and deduplicating storage appliances, the mount server role is assigned to the backup server.
  • Veeam Backup & Replication console. The mount server role is also assigned to a machine on which the Veeam Backup & Replication console is installed. Note that this type of mount server is not registered in the Veeam Backup & Replication configuration database.
For scale-out backup repositories, you must define the mount server for every extent.

If you do not want to use default mount servers, you can assign the mount server role to any Microsoft Windows machine in the backup infrastructure. It is recommended that you configure at least one mount server in each site and associate this mount server with the backup repository residing in this site. The mount server and backup repository must be located as close to each other as possible. In this case, you will be able to keep the VM traffic in one site.

Mount Server
Services and Components
On the mount server machine, Veeam Backup & Replication installs the Veeam Mount Service. The Veeam Mount Service requires .NET 4.5.2. If .NET 4.5.2 is not installed on the machine, Veeam Backup & Replication will install it automatically.

Requirements to Mount Server
The machine to which you assign the mount server role must meet the following requirements:
  • You can assign the role of a mount server to Microsoft Windows machines (physical or virtual).
  • You can assign the role of a mount server to 64-bit machines only.
  • The mount server must have access to the backup repository with which it is associated and to the original VM (VM to which you restore files or application items). For restore from storage snapshots, the mount server must also have access to the ESX(i) host on which the temporary VM is registered.

 

Veeam Backup Enterprise Manager

Veeam Backup Enterprise Manager is an optional component intended for distributed enterprise environments with multiple backup servers. Veeam Backup Enterprise Manager federates backup servers and offers a consolidated view of these servers through a web browser interface. You can centrally control and manage all jobs through a single "pane of glass", edit and clone jobs, monitor job state and get reporting data across all backup servers. Veeam Backup Enterprise Manager also enables you to search for VM guest OS files in all current and archived backups across your backup infrastructure, and restore these files in one click.

Veeam Backup Enterprise Manager can be installed on a physical or virtual machine. You can deploy it on the backup server or use a dedicated machine.

Veeam Backup Enterprise Manager uses the following services and components:
  • Veeam Backup Enterprise Manager Service coordinates all operations of Veeam Backup Enterprise Manager, aggregates data from multiple backup servers and provides control over these servers.
  • Veeam Backup Enterprise Manager Configuration Database is used by Veeam Backup Enterprise Manager for storing data. The database instance can be located on a SQL Server installed either locally (on the same machine as Veeam Backup Enterprise Manager Server) or remotely.
  • Veeam Guest Catalog Service replicates and consolidates VM guest OS file system indexing data from backup servers added to Veeam Backup Enterprise Manager. Index data is stored in Veeam Backup Enterprise Manager Catalog (a folder on the Veeam Backup Enterprise Manager Server) and is used to search for VM guest OS files in backups created by Veeam Backup & Replication.

 

Veeam Backup Search

By default, Veeam Backup & Replication uses its proprietary file indexing mechanism to index VM guest OS files and let you search for them in backups with Veeam Backup Enterprise Manager. Using Veeam's proprietary mechanism is the best practice. However, you have an option to engage the Veeam Backup Search component and Microsoft Search Server in the indexing process.

To use Veeam Backup Search, you should install the Veeam Backup Search component from the installation package on a machine running Microsoft Search Server. The Veeam Backup Search server runs the MOSS Integration Service that invokes updates of index databases on Microsoft Search Server. The service also sends search queries to Microsoft Search Server which processes them and returns necessary search results to Veeam Backup Enterprise Manager.

 

Deployment Scenarios

Veeam Backup & Replication can be used in virtual environments of any size and complexity. The architecture of the solution supports onsite and offsite data protection, operations across remote sites and geographically dispersed locations. Veeam Backup & Replication provides flexible scalability and easily adapts to the needs of your virtual environment.

Before installing Veeam Backup & Replication, familiarize yourself with common deployment scenarios and carefully plan your backup infrastructure layout.
In This Section
  • Simple Deployment
  • Advanced Deployment
  • Distributed Deployment

 

Simple Deployment

In a simple deployment scenario, one instance of Veeam Backup & Replication is installed on a physical or virtual Windows-based machine. This installation is referred to as a backup server.

Simple deployment implies that the backup server performs the following:
  • It functions as a management point, coordinates all jobs, controls their scheduling and performs other administrative activities.
  • It is used as the default backup repository. During installation, Veeam Backup & Replication checks volumes of the machine on which you install the product and identifies a volume with the greatest amount of free disk space. On this volume, Veeam Backup & Replication creates the Backup folder that is used as the default backup repository.
  • It is used as a mount server and guest interaction proxy.
In this scenario, source Hyper-V servers act as backup proxies, handling job processing and transferring backup traffic directly to the target. All necessary backup proxy services are installed on source Hyper-V servers.

Simple Deployment

If you plan to back up and replicate only a small number of VMs or evaluate Veeam Backup & Replication, this configuration is enough to get you started. Veeam Backup & Replication is ready for use right out of the box — as soon as it is installed, you can start using the solution to perform backup and replication operations. To balance the load of backing up and replicating your VMs, you can schedule jobs at different times.

Simple Deployment Tip:
If you decide to use a simple deployment scenario, you can install Veeam Backup & Replication right on the Hyper-V host where VMs you want to work with reside. However, to use this Hyper-V host as the source for backup and replication, you will still need to add it to the Veeam Backup & Replication console.

In Hyper-V environments that require a large number of backup or replication activities performed, the simple deployment scheme is not appropriate due to the following reasons:
  • The backup server might not have enough disk capacity to store the required amount of backup data.
  • A significant load is placed on production servers that combine the roles of backup proxies and source hosts.
To take the overhead off the backup server and source Hyper-V servers, you can use the advanced deployment scenario.

 

Advanced Deployment

For mid-size and large-scale Hyper-V environments with a great number of backup and replication jobs, the advanced deployment scenario can be a good choice.

The advanced deployment includes the following components:
  • Virtual infrastructure servers — Hyper-V hosts used as source and target for backup and replication.
  • Backups server — a configuration and control center of the backup infrastructure.
  • Off-host backup proxy — a “data mover” component used to retrieve VM data from the source datastore, process it and deliver to the target.
  • Backup repository — a location used to store backup files and auxiliary replica files.
  • Dedicated mount servers — component required for VM guest OS files and application items restore to the original location.
  • Dedicated guest interaction proxies — components used to deploy the runtime process in Microsoft Windows VMs.
In the advanced deployment scenario, data processing is shifted from the Hyper-V server to an off-host backup proxy — a dedicated machine that is deployed on the source side, closer to the source Hyper-V host. The off-host backup proxy functions as a “data mover”, processing VM data and mediating the backup traffic from source to target. Therefore, the job processing overhead and data transport is offloaded from the source Hyper-V host.

In the advanced deployment scenario, backup data is no longer stored to the backup repository on the backup server. Instead, data is transported to dedicated backup repositories. The backup server becomes a “manager” for off-host backup proxies and backup repositories.


Advanced Deployment
With the advanced deployment scenario, you can expand your backup infrastructure horizontally in a matter of minutes to meet your data protection requirements. Instead of growing the number of backup servers or constantly tuning job scheduling, you can install multiple backup infrastructure components and distribute the backup workload among them. The installation process is fully automated, which simplifies deployment and maintenance of the backup infrastructure in your virtual environment.

In virtual environments with several proxies, Veeam Backup & Replication dynamically distributes the backup traffic among these proxies. A job can be explicitly mapped to a specific proxy. Alternatively, you can let Veeam Backup & Replication choose an off-host backup proxy.

In this case, Veeam Backup & Replication will check settings of available backup proxies and select the most appropriate one for the job. The backup proxy should have access to the source and target hosts, and to backup repositories to which files will be written.

To regulate the backup load, you can specify the maximum number of concurrent tasks per backup proxy and set up throttling rules to limit the proxy bandwidth. For a backup repository, you can set the maximum number of concurrent tasks and define a combined data rate.

 

Distributed Deployment

The distributed deployment scenario is recommended for large geographically dispersed virtual environments with multiple backup servers installed across different sites. These backup servers are federated under Veeam Backup Enterprise Manager — an optional component that provides centralized management and reporting for these servers through a web interface.

Distributed Deployment
Veeam Backup Enterprise Manager collects data from backup servers and enables you to run backup and replication jobs across the entire backup infrastructure through a single "pane of glass", edit them and clone jobs using a single job as a template. It also provides reporting data for various areas (for example, all jobs performed within the last 24 hours or 7 days, all VMs engaged in these jobs and so on). 

Using indexing data consolidated on one server, Veeam Backup Enterprise Manager provides advanced capabilities to search for VM guest OS files in VM backups created on all backup servers (even if they are stored in repositories on different sites), and recover them in a single click. Search for VM guest OS files is enabled through Veeam Backup Enterprise Manager itself; to streamline the search process, you can optionally deploy a Veeam Backup Search server in your backup infrastructure.

With flexible delegation options and security roles, IT administrators can delegate the necessary file restore or VM restore rights to authorized personnel in the organization – for example, allow database administrators to restore Oracle or SQL server VMs.

If you use Veeam Backup Enterprise Manager in your backup infrastructure, you do not need to install licenses on every backup server you deploy. Instead, you can install one license on the Veeam Backup Enterprise Manager server and it will be applied to all servers across your backup infrastructure. This approach simplifies tracking license usage and license updates across multiple backup servers.

 

Resource Scheduling

With its built-in mechanism of resource scheduling, Veeam Backup & Replication is capable to automatically select and use optimal resources to run configured jobs. Resource scheduling is performed by the Veeam Backup Service running on the backup server. When a job starts, it communicates with the service to inform it about the resources it needs. The service analyzes job settings, parameters specified for backup infrastructure components, current load on the components, and automatically allocates optimal resources to the job.

For resource scheduling, Veeam Backup Service uses a number of settings and features:
In This Section
  • Network Traffic Throttling and Multithreaded Data Transfer
  • Limiting the Number of Concurrent Tasks
  • Limiting Read and Write Data Rates for Backup Repositories
  • Detecting Performance Bottlenecks
  • Data Processing Modes

 

Network Traffic Throttling and Multithreaded Data Transfer

To limit the impact of Veeam Backup & Replication tasks on network performance, you can throttle network traffic for jobs. Network traffic throttling prevents jobs from utilizing the entire bandwidth available in your environment and makes sure that enough traffic is provided for other network operations. It is especially recommended that you throttle network traffic if you perform offsite backup or replicate VMs to a DR site over slow WAN links.

Network traffic throttling is implemented through rules. Network throttling rules apply to components in the Veeam backup infrastructure, so you do not have to make any changes to the network infrastructure.

Network traffic throttling rules are enforced globally, at the level of the backup server. Every rule limits the maximum throughput of traffic going between backup infrastructure components on which Veeam Data Mover Services are deployed. Depending on the scenario, traffic can be throttled between the following components:
  • Backup to a Microsoft Windows or Linux backup repository: a backup proxy (onhost or offhost) and backup repository
  • Backup to an SMB share, EMC Data Domain and HPE StoreOnce: backup proxy (onhost or offhost) and gateway server
  • Backup copy: source and target backup repositories or gateway sever(s), or WAN accelerators (if WAN accelerators are engaged in the backup copy process)
  • Replication: source and target backup proxies (onhost or offhost) or WAN accelerators (if WAN accelerators are engaged in the replication process)
  • Backup to tape: backup repository and tape server
Rules are set for a pair of IP address ranges and are applied to the source and target components between which data is transferred over the network. The range can include a single IP address.

When a new job starts, Veeam Backup & Replication checks network traffic throttling rules against a pair of components assigned for the job. If the source and target IP addresses fall into specified IP ranges, the rule is applied. For example, if for a network traffic throttling rule you specify 192.168.0.1 – 192.168.0.255 as the source range and 172.16.0.1 – 172.16.0.255 as the target range, and the source component has IP address 192.168.0.12, while the target component has IP address 172.16.0.31, the rule will be applied. The network traffic going from source to target will be throttled.

Network Traffic Throttling and Multithreaded Data Transfer

Network Traffic Throttling and Multithreaded Data Transfer Note:
Throttling rules are reversible — they function in two directions. If the IP address of the component on the source side falls into the target IP range, and the IP address of the component on the target side falls into the source IP range, the rule will be applied in any case. 

Veeam Backup & Replication equally splits available bandwidth between all jobs that use backup infrastructure components to which a network throttling rule applies. For example, if you run one job that uses a pair of backup infrastructure components to which the rule applies, the job will get the entire bandwidth allowed by the rule. If you run two jobs at a time, the allowed bandwidth will be equally split between them. As soon as one of the jobs completes, the bandwidth assigned to it will be freed, and the remaining job will use the entire bandwidth allowed by the rule.

Network Traffic Throttling and Multithreaded Data Transfer

Throttling rules can be scheduled to only be active during specific time intervals (for example, during business hours). This way, you can minimize the impact of job performance spikes on the production network. Alternatively, you can select to apply throttling rules regardless of the time.

Multithreaded Data Transfer
In addition to traffic throttling, Veeam Backup & Replication offers another possibility for network traffic management — management of data transfer connections. Normally, within one backup session Veeam Backup & Replication opens five parallel TCP/IP connections to transfer data from source to target. Multithreaded data transfer increases the transfer speed but can place additional load on the network.

If required, you can disable multithreaded data transfer and limit the number of connections per session to one.

Network Traffic Throttling and Multithreaded Data Transfer Note:
Veeam Backup & Replication performs a CRC check for the TCP traffic going between the source and the target. When you perform backup and replication operations, Veeam Backup & Replication calculates checksums for data blocks going from the source. On the target, it re-calculates checksums for received data blocks and compares them to the checksums created on the source. If the CRC check fails, Veeam Backup & Replication automatically re-sends data blocks without any impact on the job.

 

Limiting the Number of Concurrent Tasks

To avoid overload of backup proxies and backup repositories, Veeam Backup & Replication allows you to limit the number of concurrent tasks performed on a backup proxy (either on-host or off-host) or targeted at a backup repository.

Before processing a new task, Veeam Backup & Replication detects what backup infrastructure components (backup proxies and repositories) will be involved. When a new job starts, Veeam Backup & Replication analyzes the list of VMs that the job includes, and creates a separate task for each disk of every VM to be processed. Tasks in the job can be processed in parallel (that is, VMs and VM disks within a single job can be processed simultaneously), optimizing your backup infrastructure performance and increasing the efficiency of resource usage.

Limiting the Number of Concurrent Tasks Note:
To use this capability, proxy server(s) should meet system requirements – each task requires a single CPU core, so for two tasks to be processed in parallel, 2 cores is the recommended minimum. Parallel VM processing must also be enabled in Veeam Backup & Replication options.

Task limiting is performed by the Veeam Backup Service that is aware of all backup proxies and backup repositories connected to it, and settings specified for these backup proxies and repositories (namely, the number of allowed concurrent tasks).

When a job starts, it informs the Veeam Backup Service about its task list and polls the service about allocated resources to its tasks at a 10 second interval after that. Before a new task targeted at a specific backup proxy or repository starts, the Veeam Backup Service checks the current workload (the number of tasks currently working with the proxy or repository) and the number of allowed tasks per this component. If this number is exceeded, a new task will not start until one of the currently running tasks is finished.

 

Limiting Read and Write Data Rates for Backup Repositories

Veeam Backup & Replication can limit the speed with which Veeam Backup & Replication must read and write data to/from the backup repository. The data read and write speed is controlled with the Limit read and write data rates to MB/s option that you can enable in the backup repository settings.

Limiting Combined Rate for Backup Repositories

The Veeam Backup Service is aware of read and write data rate settings configured for all backup repositories in the backup infrastructure. When a job targeted at a backup repository starts, the Veeam Backup Service informs the Veeam Data Mover Service running on this backup repository about the allowed read/write speed set for this repository so that the Veeam Data Mover Service can limit the read/write speed to the specified value.

If the backup repository is used by a number of tasks simultaneously, Veeam Backup & Replication splits the allowed read/write speed rate between these tasks equally. Note that the specified limit defines the allowed read speed and the allowed write speed at the same time.

For example, you set the Limit read and write data rates to option to 8 MB/s and start two backup jobs. Each job processes 1 VM with 1 VM disk. In this case, Veeam Backup & Replication will create 2 tasks and target them at the backup repository. The data write rate will be split between these 2 tasks equally: 4 MB/s for one task and 4 MB/s for the other task.

If at this moment you start some job reading data from the same backup repository, for example, a backup copy job, Veeam Backup & Replication will assign the read speed rate equal to 8 MB/s to this job. If you start 2 backup copy jobs at the same time, Veeam Backup & Replication will split the read speed rate between these 2 jobs equally: 4 MB/s for one backup copy job and 4 MB/s for the other backup copy job.

 

Detecting Performance Bottlenecks

As any backup application handles a great amount of data, it is important to make sure the data flow is efficient and all resources engaged in the backup process are optimally used. Veeam Backup & Replication provides advanced statistics about the data flow efficiency and lets you identify bottlenecks in the data transmission process.

Veeam Backup & Replication processes VM data in cycles. Every cycle includes a number of stages:
  1. Reading VM data blocks from the source
  2. Processing VM data on the backup proxy
  3. Transporting data over the network
  4. Writing data to the target
When one data processing cycle is over, the next cycle begins. VM data therefore goes over the “data pipe”.

Detecting Performance Bottlenecks

To evaluate the data pipe efficiency, Veeam Backup & Replication analyzes performance of all components in the data flow working as the cohesive system, and evaluates key factors on the source and target sides. Veeam Backup & Replication checks the following points in the data pipe:
  1. Source — source disk reader component responsible for retrieving data from the source storage.
  2. Proxy — backup proxy component responsible for processing VM data.
  3. Source WAN accelerator — WAN accelerator deployed on the source side. Used for backup copy and replication jobs working via WAN accelerators.
  4. Network — network queue writer component responsible for getting processed VM data from the backup proxy and sending it over the network to the backup repository or another backup proxy.
  5. Target WAN Accelerator — WAN accelerator deployed on the target side. Used for backup copy and replication jobs working via WAN accelerators.
  6. Target — target disk writer component (backup storage or replica datastore).
The resource usage level for these points is evaluated in percent. This percent rate defines the amount of time for which components are busy during the job. An efficient data flow assumes that there is no latency at any point of the data pipe, and all its components work for approximately equal amount of time.

If any of the components operates inefficiently, there may appear a bottleneck in the data path. The insufficient component will work 100% of time while the others will be idling, waiting for data to be transferred. As a result, the whole data flow will slow down to the level of the slowest point in the data path, and the overall time of data processing will increase.

To identify a bottleneck in the data path, Veeam Backup & Replication detects the component with the maximum workload: that is, the component that works for the most time of the job. For example, you use a low-speed storage device as the backup repository. Even if VM data is retrieved from the SAN storage on the source side and transported over a high-speed link, VM data flow will still be impaired at the backup repository.

The backup repository will be trying to consume transferred data at the rate that exceeds its capacity, and the other components will stay idle. As a result, the backup repository will be working 100% of job time, while other components may be employed, for example, for 60% only. In terms of Veeam Backup & Replication, such data path will be considered insufficient.

The bottleneck statistics for a job is displayed in the job session data. The bottleneck statistics does not necessarily mean that you have a problem in your backup infrastructure. It simply informs you about the weakest component in the data path. However, if you feel that the job performance is low, you may try taking some measures to get rid of the bottleneck. For example, in the case described above, you can limit the number of concurrent tasks for the backup repository.

Detecting Performance Bottlenecks 

Throttling as Bottleneck
In addition to main points in the data pipe, Veeam Backup & Replication may report throttling as a bottleneck. This can happen in the following cases:
  • If you limit the read and write data rates for a backup repository, a backup repository may become a bottleneck. Veeam Backup & Replication will report Throttling in the bottleneck statistics.
  • If you set up network throttling rules, network may become a bottleneck. Veeam Backup & Replication will report Throttling in the bottleneck statistics.

 

Data Processing Modes

Veeam Backup & Replication can process VMs in the job and VM disks in parallel or sequentially. The data processing mode is a global setting: it takes effect for all jobs configured on the backup server.

Parallel Data Processing
By default, Veeam Backup & Replication works in the parallel data processing mode. If a job includes several VMs or VMs in the job have several disks, VMs and VM disks are processed concurrently.

Parallel data processing optimizes the backup infrastructure performance and increases efficiency of resource usage. It also reduces the time of VM snapshots being open and mitigates the risk of long snapshot commit.

Data Processing Modes

If you choose to process VM data in parallel, check task limitation settings for components in your backup infrastructure and make sure that these components have sufficient compute resources to support parallel processing. 

Task limitation settings define the number of tasks that the backup infrastructure component can perform concurrently, or at the same moment. The maximum number of concurrent tasks that a backup proxy or repository can perform depends on the number of CPU cores available on this backup proxy or backup repository. It is strongly recommended that you assign task limitation settings using the following rule: 1 task = 1 CPU core. For example, if a backup proxy has 4 CPU cores, it is recommended that you limit the number of concurrent tasks for this backup proxy to 4.

Task limits specified for backup proxies and backup repositories influence the job performance. For example, you add a VM with 4 disks to a job and target this job at the backup proxy that can process maximum 2 tasks concurrently. In this case, Veeam Backup & Replication will create 4 tasks (1 task per each VM disk) and start processing 2 tasks in parallel. The other 2 tasks will be pending.


Data Processing Modes Note:
When you limit the number of tasks for the backup repository, you should also consider the storage throughput. If the storage system is not able to keep up with the number of tasks that you have assigned, it will be the limiting factor. It is recommended that you test components and resources of your backup infrastructure to define the workload that they can handle.







Data Processing Modes

Subsequent Data Processing
If you do not want to use parallel data processing, you can disable it. In this case, Veeam Backup & Replication will process VMs and VM disks in the job one by one, sequentially.
Even if you disable parallel data processing, backup proxies and backup repositories can still process tasks from different jobs in parallel. For example:
  1. You set up the backup proxy to process 2 tasks simultaneously.
  2. You configure 2 backup jobs, each processing 1 VM with 1 disk.
When you start backup jobs, Veeam Backup & Replication will create 2 tasks and assign these tasks to the backup proxy. The backup proxy will perform these tasks in parallel.

 

Backup

Unlike traditional backup tools designed to work with physical machines, Veeam Backup & Replication is built specifically for virtual environments. It operates at the virtualization layer and uses an image-based approach for VM backup. To retrieve VM data, no agent software needs to be installed inside the guest OS. Instead, Veeam Backup & Replication leverages VSS snapshot capabilities. When a new backup session starts, a VSS snapshot is taken to create a cohesive point-in-time copy of a VM including its configuration, OS, applications, associated data, system state and so on. Veeam Backup & Replication uses this point-in-time copy to retrieve VM data. Image-based backups can be used for different types of recovery, including Instant VM Recovery, full VM recovery, VM file recovery and file-level recovery.

Use of the image-based approach allows Veeam Backup & Replication to overcome shortfalls and limitations of traditional backup (such as, the necessity to provide guest OS credentials for every VM, significant resource overhead on the VM and hypervisor during the backup process, management overhead and so on). It also helps streamline the restore process — to recover a single VM, there is no need to perform multiple restore operations. Veeam Backup & Replication uses a cohesive VM image from the backup to restore a VM to the required state without the necessity for manual reconfiguration and adjustment.

In Veeam Backup & Replication, backup is a job-driven process where one backup job can be used to process one or more VMs. A job is a configuration unit of the backup activity. Essentially, the job defines when, what, how and where to back up. It indicates what VMs should be processed, what components should be used for retrieving and processing VM data, what backup options should be enabled and where to save the resulting backup file. Jobs can be started manually by the user or scheduled to run automatically.

The resulting backup file stores compressed and deduplicated VM data. All backup files created by the job are located in a dedicated job folder on a backup repository. Veeam Backup & Replication creates and maintains the following types of backup files:
  • Full backup (.vbk) to store copies of full VM images
  • Backup increment (.vib or .vrb) to store incremental changes to VM images
  • Backup metadata (.vbm) to provide information on the backup job, VMs in the backup, number and structure of backup files, restore points, and so on. The metadata file facilitates import of backups or mapping of backup jobs to existing backups.
To back up VMs, you can use one of three available methods:
  • Foverver forward incremental backup
  • Forward incremental backup
  • Reverse incremental backup
Regardless of the method you use, the first run of a job creates a full backup of VM image. Subsequent job runs are incremental — Veeam Backup & Replication copies only those data blocks that have changed since the last backup job run. To keep track of changed data blocks, Veeam Backup & Replication uses its proprietary changed block tracking mechanism.
In This Section
  • Backup of VMs on Local Storage and CSV
  • Backup of VMs on SMB3
  • Backup Architecture
  • Backup Methods
  • Retention Policy
  • Per-VM Backup Files
  • Changed Block Tracking
  • Data Compression and Deduplication
  • Data Exclusion
  • Transaction Consistency
  • Guest Processing
  • Job Scheduling
  • VeeamZIP
  • Quick Backup
  • Health Check for Backup Files
  • Compact of Full Backup File

 

Backup of VMs on Local Storage and CSV

Veeam Backup & Replication performs backup of Hyper-V VMs whose disks are located on the local storage and Cluster Shared Volume (CSV). In contrast to traditional backup tools that deploy an agent inside the VM guest OS and back up from within a VM, Veeam Backup & Replication uses a Veeam Data Mover Service running on the Hyper-V host or a Veeam Data Mover Service running on the off-host backup proxy. A VM is treated as an object from the perspective of the Hyper-V host — Veeam Backup & Replication captures the VM configuration and state along with VM VHD/VHDX's and creates an image-based backup of a VM.

To perform backup of Hyper-V VMs, Veeam Backup & Replication leverages the VSS framework and Hyper-V VSS components. It acts as a VSS requestor and communicates with the VSS framework. Veeam Backup & Replication obtains from VSS information about available VSS components, prescribes what components should be used, identifies volumes where files of the necessary VMs are located and triggers the VSS coordinator to create volume snapshots.

Before a snapshot of a volume is created, VMs on the volume must be prepared for the snapshot — that is, data in the VM must be in a state suitable for backup. Veeam Backup & Replication uses three methods to quiesce Hyper-V VMs on the volume: online backup, offline backup and crash-consistent backup.
Whenever possible, Hyper-V VSS uses online backup to quiesce VMs. If online backup cannot be performed, one of the other two methods is used to prepare a VM for a volume snapshot.
  • If online backup is not possible, Veeam Backup & Replication will fail over to the crash-consistent backup.
  • If you do not want to produce a crash-consistent backup, you can configure your backup jobs to use the offline backup method instead.
Backup of VMs on Local Storage and CSV Note:
Veeam Backup & Replication does not fail over to the crash-consistent backup mode if you enable application-aware processing for a job and select the Require successful processing option. In such situation, if application-aware processing fails, Veeam Backup & Replication will simply terminate the job with the Error status.

 

Online Backup

Online backup is the recommended backup method for Hyper-V VMs. This type of backup requires no downtime — VMs remain running for the whole period of backup and users can access them without any interruption. Online backup can only be performed if a VM meets a number of conditions: the VM runs under a VSS-aware guest OS, Hyper-V Integration Services are installed inside the guest OS, the backup integration is enabled, and some other requirements. For a complete list of conditions required for online backup, refer to Microsoft Hyper-V documentation.

For online backup, Veeam Backup & Replication uses a native Hyper-V approach. To quiesce VM data, Hyper-V uses two VSS frameworks that work at two different levels and communicate with each other:
  • The VSS framework at the level of the Hyper-V host. This VSS framework is responsible for taking a snapshot of the volume on which VMs are located (this snapshot is also called external snapshot).
  • The VSS framework inside the VM guest OS. This VSS framework is responsible for quiescing data of VSS-aware applications running inside the VM and creating a snapshot inside the guest OS (this snapshot is also called internal snapshot).
Online backup includes the following steps:
  1. Veeam Backup & Replication interacts with the Hyper-V host VSS Service and requests backup of specific VMs.
  2. The VSS Writer on the Hyper-V host passes the request to the Hyper-V Integration Components (HV-IC) installed inside the VM guest OS.
  3. The HV-IC, in its turn, acts as a VSS Requestor for the VSS framework inside the VM — it communicates with the VSS framework installed in the VM guest OS and requests backup of VSS-aware applications running inside this VM.
  4. The VSS Writers within the VSS-aware applications inside the guest OS are instructed to get the application data to a state suitable for backup.
  5. After the applications are quiesced, the VSS inside the VM takes an internal snapshot within the VM using a VSS software provider in the VM guest OS.
  6. After the internal snapshot is taken, the VM returns from the read-only state to the read-write state and operations inside the VM are resumed. The created snapshot is passed to the HV-IC.
  7. The HV-IC notifies the hypervisor that the VM is ready for backup.
  8. The Hyper-V host VSS provider takes a snapshot of a volume on which the VM is located (external snapshot).
  9. The volume snapshot is presented to Veeam Backup & Replication. Veeam Backup & Replication reads VM files from the volume snapshot using one of two backup modes — on-host backup or off-host backup. After the backup is completed, the snapshot is deleted.
Online Backup
Internal and external snapshots are taken one after another, with a little time difference. During this time interval, the VM on the volume is not frozen – its applications and OS are working as usual. For this reason, when the external snapshot is created, there may remain unfinished application transactions inside the VM, and this data can be lost during backup.

To make sure the VM data is consistent at the moment of backup, Hyper-V VSS Writer performs additional processing inside the created external snapshot — this process is also known as auto-recovery.
Auto-recovery is performed when a volume snapshot is taken. This process includes the following steps:
  1. Right after the snapshot of a volume is taken, Hyper-V host VSS allows the Hyper-V host VSS Writer time to update data inside the external snapshot before it is permanently changed to the read-only state.
  2. The Hyper-V host VSS Writer rolls back a VM on the external snapshot to the state of the internal snapshot. All changes that took place after the internal snapshot was taken are discarded – this way, VM data inside the external snapshot is brought to a completely consistent state suitable for backup. At the same time, the internal snapshot inside the VM guest OS is deleted.
  3. As a result, you have a VM on the production volume, and a consistent volume snapshot that Veeam Backup & Replication uses for backup.
Online Backup Note:
Auto-recovery may take up to several minutes.

Offline Backup

Offline backup (or backup via saved state) is another native Hyper-V approach to quiescing VMs before taking a volume snapshot. This type of backup requires some downtime of a VM. When a VM is backed up, the Hyper-V VSS Writer forces the VM into the saved state to create a stable system image.
Offline backup is performed in the following way:
  1. Veeam Backup & Replication interacts with the Hyper-V host VSS Services and requests backup of specific VMs.
  2. The Hyper-V host VSS Writer forces a VM into the saved state for several seconds. The VM OS hibernates and the content of the system memory and CPU is written to a dump file.
  3. The Hyper-V host VSS provider takes a snapshot of a volume on which the VM is located. After the snapshot is created, the VM returns to the normal state.
  4. The volume snapshot is presented to Veeam Backup & Replication. Veeam Backup & Replication reads VM files from the volume snapshot using one of two backup modes — on-host backup or off-host backup. After the backup is completed, the snapshot is deleted.
Offline backup may be inappropriate — it incurs downtime to a VM and does not produce transactionally consistent backups and replicas as Veeam Backup & Replication does not interact with the VSS framework on the VM guest OS during backup or replication. As an alternative to offline backup, Veeam Backup & Replication offers the crash-consistent backup method for those cases when online backup is not possible and offline backup is unsuitable.

Offline Backup

 

Crash-Consistent Backup

Crash-consistent backup is Veeam’s method of creating crash-consistent VM images. A crash-consistent image can be compared to the state of a VM that has been manually reset. Unlike offline backup, crash-consistent backup does not involve any downtime.


Crash-Consistent Backup Important!
Crash-consistent backup does not preserve data integrity of open files of transactional applications on the VM guest OS and may result in data loss.


Crash-consistent backup is performed in the following way:
  1. Veeam Backup & Replication interacts with the Hyper-V host VSS Services and requests backup of specific VMs.
  2. The Hyper-V host VSS Writer notifies the VSS provider that volume snapshots can be taken.
  3. The Hyper-V host VSS provider creates a snapshot of the requested volume.
  4. The volume snapshot is presented to Veeam Backup & Replication. Veeam Backup & Replication reads VM files from the volume snapshot using one of two backup modes — on-host backup or off-host backup. After the backup is completed, the snapshot is deleted.
Crash-Consistent Backup

 

Backup Modes

Veeam Backup & Replication offers two modes for processing volume shadow copies – on-host backup and off-host backup. The difference between the two modes lies in the location where VM data is processed.

In This Section
  • On-Host Backup
  • Off-Host Backup

 

On-Host Backup

During on-host backup, VM data is processed on the source Hyper-V host where VMs you want to back up or replicate reside. All processing operations are performed directly on the source Hyper-V host. For this reason, on-host backup may result in high CPU usage and network overhead on the host system.

The on-host backup process includes the following steps:
  1. Veeam Backup & Replication triggers a snapshot of the necessary volume.
  2. The Veeam Data Mover Service uses the created volume snapshot to retrieve VM data; it processes the VM data and copies it to the destination.
  3. Once the backup process is complete, the volume snapshot is deleted.
On-Host Backup

Assigning the Role of the On-Host Backup Proxy in CSV

In Veeam Backup & Replication, the role of the backup proxy is assigned to the Hyper-V host in CSV by the following rules:
  • In case you perform backup or replication of VMs whose disks are located on the CSV in Microsoft Windows Server 2012 or Microsoft Windows Server 2012 R2 and Microsoft CSV Software Shadow Copy Provider is used for snapshot creating, Veeam Backup & Replication assigns the role of the on-host backup proxy to the Hyper-V host owning the CSV. If VM disks are located on different CSV's, Veeam Backup & Replication may use several on-host backup proxies, which are the corresponding Hyper-V hosts owning the CSV's.
  • In case you perform backup or replication of VMs whose disks are located on the CSV in Microsoft Windows 2008R2 and a VSS software or hardware provider is used for snapshot creation, Veeam Backup & Replication assigns the role of the on-host backup proxy to the Hyper-V host on which the processed VM is registered.

 

Off-Host Backup

In the off-host backup mode, backup processing is shifted from the source Hyper-V host to a dedicated machine – an off-host backup proxy. The off-host backup proxy acts as a “data mover”– the Veeam Data Mover Service running on it retrieves VM data from the source datastore, processes it and transfers to the destination. This type of backup does not impose load on the Hyper-V host — while resource intensive backup operations are performed on the off-host backup proxy, production hosts remain unaffected.

To perform off-host backup, Veeam Backup & Replication uses transportable shadow copies. The transportable shadow copy technology enables you to create a snapshot of a data volume on one server and import, or mount, it onto another server within the same subsystem (SAN) for backup and other purposes. The transport process is accomplished in a few minutes, regardless of the amount of the data.

The process is performed at the SAN storage layer so it does not impact the host CPU usage or network performance.

To be able to perform off-host backup, you must meet the following requirements:
  1. You must configure an off-host backup proxy. The role of an off-host backup proxy can be assigned only to a physical Microsoft Windows 2008 Server R2 machine with the Hyper-V role enabled, Microsoft Windows Server 2012 machine with the Hyper-V role enabled or Microsoft Windows Server 2012 R2 machine with the Hyper-V role enabled.
Note that the version of the Hyper-V host and off-host backup proxy must coincide. For example, if you use a Microsoft Windows 2008 Server R2 machine with the Hyper-V role enabled as a Hyper-V host, you should deploy the off-host backup proxy on a Microsoft Windows 2008 Server R2 machine with the Hyper-V role enabled.

For evaluation and testing purposes, you can assign the off-host backup proxy role to a VM. To do this, you must enable the Hyper-V role on this VM (use nested virtualization). However, it is not recommended that you use such off-host backup proxies in the production environment.
  1. In the properties of a backup or replication job, the off-host backup method must be selected. If necessary, you can point the job to a specific proxy.
  2. The source Hyper-V host and the off-host backup proxy must be connected (through a SAN configuration) to the shared storage.
  3. To create and manage volume shadow copies on the shared storage, you must install and properly configure a VSS hardware provider that supports transportable shadow copies on the off-host proxy and Hyper-V host. Typically, when configuring a VSS hardware provider, you need to specify a server controlling the LUN and disk array credentials to provide access to the array.
The VSS hardware provider is usually distributed as a part of client components supplied by the storage vendor. Any VSS hardware provider certified by Microsoft is supported. Note that some storage vendors may require additional software and licensing to be able to work with transportable shadow copies.
  1. If you back up VMs whose disks reside on a CSV with Data Deduplication enabled, make sure that you use a Microsoft Windows 2012 R2 machine as an off-host backup proxy and enable the Data Deduplication option on this off-host backup proxy. Otherwise, off-host backup will fail.
The off-host backup process includes the following steps:
  1. Veeam Backup & Replication triggers a snapshot of the necessary volume on the production Hyper-V host.
  2. The created snapshot is split from the production Hyper-V server and mounted to the off-host backup proxy.
  3. The Veeam Data Mover Service running on a backup proxy uses the mounted volume snapshot to retrieve VM data; the VM data is processed on the proxy server and copied to the destination.
  4. Once the backup process is complete, the snapshot is dismounted from the off-host backup proxy and deleted on the SAN.
Off-Host Backup Important!
If you plan to perform off-host backup for a Hyper-V cluster with CSV, make sure you deploy an off-host backup proxy on a host that is NOT a part of a Hyper-V cluster.
When a volume snapshot is created, this snapshot has the same LUN signature as the original volume. Microsoft Cluster Services do not support LUNs with duplicate signatures and partition layout. For this reason, volume snapshots must be transported to an off-host backup proxy outside the cluster. If the off-host backup proxy is deployed on a node of a Hyper-V cluster, a duplicate LUN signature will be generated, and the cluster will fail during backup or replication.

Off-Host Backup

 

Choosing a VSS Provider

Before you configure backup jobs, it is recommended to decide on the VSS provider that will be used to create and maintain volume shadow copies.

By default, Veeam Backup & Replication automatically selects a VSS provider on every volume. Every 4 hours it rescans all managed Hyper‑V hosts to update information on connected volumes.

Veeam Backup & Replication also collects information on software and hardware VSS providers available on every volume. If hardware providers are available, Veeam Backup & Replication will select a hardware provider. If no hardware providers are installed, the VSS system software provider will be selected to create and manage shadow copies on a volume. If necessary, however, you can assign a VSS provider on every volume manually.

If both software and hardware providers are available for a volume, it is recommended to select a hardware provider. Although software providers are generally applicable to a wider range of storage platforms, they are exposed to a number of limitations:
  • Software providers do not support transportable volume shadow copies and cannot be used for off-host backup.
  • By default, in Veeam Backup & Replication jobs working with the same volume can take up to 4 snapshots of a volume simultaneously. The number of snapshots can be increased.
  • Hardware providers work at the storage system controller level. Software providers operate at the software level, between the file system and the volume manager, and can cause a significant performance overhead on the source host.
  • (For Microsoft Windows 2008 R2) Hardware providers can work with several snapshots simultaneously: that is, if you have several jobs that work with the same volume, you can run them in parallel. If you use a software provider, Veeam Backup & Replication serializes VM processing. You will not be able to start several jobs working with the same volume simultaneously. The volume on which VM disks reside remains locked by one job for the whole period of data processing. Once the job completes, the volume becomes accessible for other jobs.
  • (For Microsoft Windows 2008 R2) Software providers are not suitable for backup on Cluster Shared Volumes (CSVs), because a significant backup window is required to back up VMs that reside on the same volume but are registered on different hosts. When a cluster node initiates a snapshot on a CSV, the CSV is switched to the Backup in Progress, Redirected Access mode.
  • If a hardware provider is used to take a snapshot in such case, the CSV stays in the redirected mode while the snapshot is taken; after a volume shadow copy is created, the CSV resumes direct I/O.
  • If a software provider is used to take a snapshot, the CSV stays in the redirected mode until the backup process completes. In cases when large virtual disks are processed, backup time can be significant.

Backup of VMs on SMB3

With Hyper-V 3.0, Microsoft provides the ability to store VM files on SMB3 file shares.

Veeam Backup & Replication introduces support for VM files residing on SMB3 shares and lets you perform backup, replication and file copy operations for such VMs without taking VMs offline. Veeam Backup & Replication works with both standalone and clustered SMB3 servers.

In general, VM quiescence and backup of VMs on SMB3 shares is similar to backup of VMs hosted on local storage and CSV. However, SMB3 brings in some specifics.

To be able to work with SMB3 shares in Veeam Backup & Replication, you must meet the following requirements:
  1. Make sure that your SMB3 shares are properly configured. For a full list of requirements for SMB3 shares, see the Requirements and supported configurations section at http://technet.microsoft.com/en-us/library/jj612865.aspx.
  2. Add the SMB3 server or SMB3 cluster hosting the necessary file shares to the Veeam Backup & Replication console. Otherwise Veeam Backup & Replication will not be able to use the changed block tracking mechanism for VMs residing on SMB3 shares.
  3. Make sure that VMs you plan to work with are not located on hidden shares or default shares like C$ or D$. When re-scanning SMB v3 file shares, Veeam Backup & Replication skips these types of shares.

 

Backup Process

For backup and replication of VMs that reside on SMB3 shares, Veeam Backup & Replication uses a native Hyper-V approach leveraging the Microsoft VSS framework. Veeam Backup & Replication acts as a VSS requestor: it communicates with the VSS framework and triggers a shadow copy of the necessary file share.

The Microsoft VSS components create a file share shadow copy and present it to

Veeam Backup & Replication, which uses the shadow copy for backup.

To properly quiesce VMs on SMB3 shares, Hyper-V uses three VSS frameworks. These frameworks work at the level of the Hyper-V host and at the level of the SMB3 file server and communicate with each other:
  1. VSS framework on the Hyper-V host (Hyper-V Host VSS). When Veeam Backup & Replication starts the backup process, it communicates directly with the VSS framework on the Hyper-V host where the VM is registered. The Hyper-V host VSS Service initiates creation of the file share shadow copy, freezes VM application writes and passes the request for shadow copy to the VSS for SMB File Shares framework. After the shadow copy is created, the Hyper-V host VSS Service returns a path to the shadow copy to Veeam Backup & Replication.
  2. VSS for SMB File Shares. This framework is Microsoft’s extension to its VSS framework. VSS for SMB File Shares provides application-consistent shadow copies of VMs on SMB3 network shares. To work with shadow copies of file shares, VSS for SMB File Shares uses two components:
  • File Share Shadow Copy Provider is a VSS provider for SMB3. The File Share Shadow Copy Provider is invoked on the Hyper-V host where the VM is registered. The provider uses VSS APIs to interact with the VSS requestor, File Share Shadow Copy Agent, and request creation of file shares shadow copies.
  • File Share Shadow Copy Agent is a VSS requestor for SMB3. The File Share Shadow Copy Agent is invoked on the SMB3 file server. The agent interacts with the local VSS framework on the SMB3 file server to create a shadow copy of the requested file share.
  1. Local VSS framework on the SMB3 file server. This framework is responsible creating a shadow copy of the volume on which the file share is located and exposing the shadow copy as a file share on the SMB3 server.
Backup Process 
Backup of VMs on SMB3 shares includes the following steps:
  1. Veeam Backup & Replication interacts with the Hyper-V host VSS Service and requests a shadow copy of the necessary file share.
  2. The Hyper-V host VSS Service sends a request to prepare a shadow copy to the Hyper-V host VSS Writer. The Hyper-V host VSS Writer flushes buffers and holds application writes on VMs.
  3. The Hyper-V host VSS Service sends a request for shadow copy creation to the File Share Shadow Copy Provider invoked on the Hyper-V host.
  4. The File Share Shadow Copy Provider relays the request to the File Share Shadow Copy Agent invoked on the SMB3 file server hosting the necessary file share.
  5. The File Share Shadow Copy Agent triggers a request for shadow copy creation to the local VSS on the SMB3 file server.
  6. The local VSS on the SMB3 file server uses the necessary shadow copy provider to create a shadow copy of the volume on which the necessary file share is located. The shadow copy is exposed as a file share on the SMB3 server. After that, application writes on VMs located on the original file share are resumed.
  7. The File Share Shadow Copy Agent returns a path to the shadow copy to the File Share Shadow Copy Provider.
  8. The File Share Shadow Copy Provider communicates this information to the Hyper-V host VSS Service.
  9. Veeam Backup & Replication retrieves information about the shadow copy properties from the Hyper-V host VSS Service.
  10. Veeam Backup & Replication uses the created shadow copy for backup. The Data Mover on the backup proxy (onhost or offhost) establishes a connection to the Data Mover on the Microsoft SMB3 server and reads CBT information from the Microsoft SMB3 server. The Data Mover on the backup proxy then retrieves VM data blocks from the shadow copy, compresses and deduplicates them, and passes to the Data Mover on the backup repository.
After backup is complete, the file share shadow copy is deleted.

Backup Process

 

Backup Modes

Veeam Backup & Replication offers two modes for processing VMs on SMB3 shares: on-host backup and off-host backup.

In This Section
  • On-Host Backup
  • Off-Host Backup

 

On-Host Backup

On-host backup of VMs on SMB3 shares is similar to on-host backup of VMs on local storage and CSV. During on-host backup, the Hyper-V VSS components, File Share Shadow Copy Provider and Veeam Data Mover Service are invoked on the source Hyper-V VSS host. The File Share Shadow Copy Agent is invoked on the SMB3 server. As a result, all data processing is accomplished directly on the source Hyper-V host and on the SMB3 server.

The on-host backup process includes the following steps:
  1. Veeam Backup & Replication triggers a shadow copy of the necessary file share. Microsoft VSS components invoked on the Hyper-V host and SMB3 server create a shadow copy of the volume on which the requested file share is located and expose the shadow copy as a file share on the SMB3 server.
  2. The Veeam Data Mover Service deployed on the Hyper-V host accesses the shadow copy file share exposed on the SMB3 server. Veeam Backup & Replication retrieves VM data from the shadow copy, processes the data and copies it to the destination.
  3. Once the backup process is complete, the shadow copy is deleted.
On-Host Backup

 

Off-Host Backup

In general, the main concept of off-host backup for VMs on SMB3 shares is similar to off-host backup of VMs on local storage or CSV. During off-host backup, the Hyper-V VSS processing operations are shifted from the source Hyper-V host to a dedicated machine — off-host backup proxy. The Veeam Data Mover Service is deployed on the off-host backup proxy, instead of the source Hyper-V host.

To be able to perform off-host backup, you must meet the following requirements:
  1. You must configure an off-host backup proxy. The role of an off-host backup proxy can be assigned only to a physical Microsoft Windows 2008 Server R2 machine with the Hyper-V role enabled, Microsoft Windows 2012 machine with the Hyper-V role enabled or Microsoft Windows 2012 R2 machine with the Hyper-V role enabled.
For evaluation and testing purposes, you can assign the off-host backup proxy role to a VM. To do this, you must enable the Hyper-V role on this VM (use nested virtualization). However, it is not recommended that you use such off-host backup proxies in the production environment.
  1. In the properties of a backup or replication job, you must select the off-host backup method. If necessary, you can assign the job to a specific proxy.
  2. The Local System account of the off-host backup proxy must have full access permissions on the SMB3 file share.
  3. The off-host backup proxy should be located in the same domain where the SMB3 server resides. Alternatively, the domain where the SMB3 server resides should be trusted by the domain in which the off-host backup proxy is located.
The off-host backup process includes the following steps:
  1. Veeam Backup & Replication triggers a shadow copy of the necessary file share. Microsoft VSS components invoked on the Hyper-V host and SMB3 server create a shadow copy of the volume on which the requested file share is located and expose the shadow copy as a file share on the SMB3 server.
  2. The Veeam Data Mover Service on the off-host backup proxy accesses the shadow copy on the SMB3 server. It retrieves VM data from the shadow copy, processes the VM data and copies it to the destination.
  3. Once the backup process is complete, the shadow copy is deleted.
Off-Host Backup

 

Backup Architecture

The backup infrastructure in a Hyper-V environment comprises the following components:
  • One or more source hosts with associated volumes
  • Off-host backup proxy server (optional)
  • One or more backup repositories
  • One or more guest interaction proxies (optional)
The source host and the backup repository produce two terminal points between which VM data is moved. Backup data is collected, transformed and transferred with the help of Veeam Data Mover Services. Veeam Backup & Replication uses a two-service architecture — one Veeam Data Mover Service interacts with the source host, and the other one interacts with the backup repository. The Veeam Data Mover Services communicate with each other and maintain a stable connection.

All backup infrastructure components engaged in the job make up a data pipe. VM data is moved over this data pipe block by block, so that processing of a single VM includes multiple processing cycles.

When a new backup session starts, Veeam Backup & Replication performs the following actions:
  1. Veeam Backup & Replication deploys the runtime process on VM guest OSes via the guest interaction proxy (for Microsoft Windows VMs) or backup server (for VMs with other OSes).
  2. The target-side Veeam Data Mover Service obtains the job instructions and communicates with the source-side Veeam Data Mover Service to begin data collection.
  3. After a VSS snapshot is created, the source-side Veeam Data Mover Service copies VM data from the volume shadow copy. While copying, the source-side Veeam Data Mover Service performs additional processing — it consolidates the content of virtual disks by filtering out zero-data blocks and blocks of swap files. During incremental job runs, the Veeam Data Mover Service retrieves only those data blocks that have changed since the previous job run (note that with changed block tracking enabled, the speed of incremental backup dramatically increases). Copied blocks of data are compressed and moved from the source-side Veeam Data Mover Service to the target-side Data Mover Service.
  4. The target-side Veeam Data Mover Service deduplicates similar blocks of data and writes the result to the backup file in the backup repository.
Veeam Backup & Replication supports a number of backup scenarios that depend on the type of repository you use and its location.

 

Onsite Backup


If you choose to back up to an onsite Windows or Linux repository, Veeam Backup & Replication will start the target-side Veeam Data Mover Service on the Windows or Linux repository server. The source-side Veeam Data Mover Service can be hosted either on the source host or on a dedicated off-host backup proxy, depending on the backup mode you use (on-host or off-host). Backup data is sent from the source host to the backup repository over LAN.

Onsite Backup

To back up to an onsite SMB share, you need a Microsoft Windows-based gateway server that has access to the SMB share. This can be either the backup server or another Microsoft Windows server added to the Veeam Backup & Replication console. In this scenario, Veeam Backup & Replication starts the target-side Veeam Data Mover Service on the gateway server. The source-side Veeam Data Mover Service can be hosted either on the source host or on a dedicated off-host backup proxy, depending on the backup mode you use (on-host or off-host).

Onsite Backup

If you choose to back up VMs to an SMB share and do not specify a gateway server explicitly, Veeam Backup & Replication will start the source-side and target-side Veeam Data Mover Service on the proxy server. In the on-host backup scenario, Veeam Data Mover Services will be started on the source Hyper-V host. In the off-host backup scenario, Veeam Data Mover Services will be started on the off-host backup proxy.

Onsite Backup

 

Offsite Backup

The common requirement for offsite backup is that one Veeam Data Mover Service runs in the production site (closer to the source datastore), and the other Veeam Data Mover Service runs in the remote target site (closer to the backup repository). During backup, Veeam Data Mover Services maintain a stable connection, which allows for uninterrupted operation over WAN or slow links.

If you choose to back up to an offsite Windows or Linux repository, Veeam Backup & Replication will start the target-side Veeam Data Mover Service on the Windows or Linux repository server. The source-side Veeam Data Mover Service can be hosted either on the source host or on a dedicated off-host backup proxy, depending on the backup mode you use (on-host or off-host). Backup data is sent from the source to the backup repository over WAN.

Offsite Backup

If you choose to back up to an offsite SMB share in the on-host mode, you should deploy an additional Microsoft Windows-based gateway server in the remote site and point the SMB share to this gateway server in the backup repository settings. In this scenario, Veeam Backup & Replication starts the target-side Veeam Data Mover Service on the gateway server. The source-side Veeam Data Mover Service can be hosted either on the source host or on a dedicated off-host backup proxy in the source site, depending on the backup mode you use (on-host or off-host).

Offsite Backup

 

Backup Methods

Veeam Backup & Replication provides three methods for creating backup chains:
  • Forever forward incremental backup
  • Forward incremental backup
  • Reverse incremental backup

 

Forever Forward Incremental Backup

The forever forward incremental backup method produces a backup chain that consists of the first full backup and a set of forward incremental backups following it.

Veeam Backup & Replication creates a forever forward incremental backup chain in the following way:
  1. During the first run of a backup job, Veeam Backup & Replication creates a full backup file (VBK) in the backup repository.
  2. During subsequent backup job sessions, Veeam Backup & Replication copies only VM data blocks that have changed since the last performed backup (full or incremental) and saves these blocks as an incremental backup file (VIB) in the backup chain.
After adding a new restore point to the backup chain, Veeam Backup & Replication checks the retention policy set for the job. If Veeam Backup & Replication detects an outdated restore point, it transforms the backup chain to make room for the most recent restore point

Forever Forward Incremental Backup
To use this backup method, you must select the following options in the backup job settings:
  1. Select the Incremental backup mode.
  2. Do not enable synthetic full backups and/or active full backups. If you enable synthetic and/or active full backups, Veeam Backup & Replication will produce a forward incremental backup chain.
Forever Forward Incremental Backup

Forward Incremental Backup

The forward incremental backup method produces a backup chain that consists of the first full backup and a set of forward incremental backups following it. Additionally, the forward incremental backup chain contains synthetic full and/or active full backups that “split” the backup chain into shorter series.

Veeam Backup & Replication creates a forward incremental backup chain in the following way:
  1. During the first run of a backup job, Veeam Backup & Replication creates a full backup file (VBK) in the backup repository.
  2. During subsequent backup job sessions, Veeam Backup & Replication copies only VM data blocks that have changed since the last performed backup (full or incremental) and saves these blocks as an incremental backup file (VIB) in the backup chain.
  3. On a day when the synthetic full or active full backup is scheduled, Veeam Backup & Replication creates a full backup file (VBK) and adds it to the backup chain. Incremental restore points produced after this full backup file use it as a new starting point.
After adding a new restore point to the backup chain, Veeam Backup & Replication checks the retention policy set for the job. If Veeam Backup & Replication detects an outdated restore point, it attempts to remove this point from the backup chain. 

Forward Incremental Backup
The forward incremental backup with synthetic full backup enabled is a default method for backup chain creation. To use the forward incremental backup method, you can leave the default settings or select the following options in the backup job settings:
  1. Select the Incremental backup mode.
  2. Enable synthetic full backups and/or active full backups. If the synthetic full backup and/or active full backups are not enabled, Veeam Backup & Replication will produce a forever forward incremental backup chain.
Forward Incremental Backup

 

Reverse Incremental Backup

The reverse incremental backup method produces a backup chain that consists of the last full backup and a set of reverse incremental backups preceding it.

Veeam Backup & Replication creates a reverse incremental backup chain in the following way:
  1. During the first run of a backup job, Veeam Backup & Replication creates a full backup file (VBK) in the backup repository.
  2. During subsequent backup job sessions, Veeam Backup & Replication copies only VM data blocks that have changed since the last performed backup. Veeam Backup & Replication “injects” copied data blocks into the full backup file to rebuild it to the most recent state of the VM. Additionally, Veeam Backup & Replication creates a reverse incremental backup file (VRB) containing data blocks that are replaced when the full backup file is rebuilt, and adds this reverse incremental backup before the full backup in the backup chain.
After adding a new restore point to the backup chain, Veeam Backup & Replication checks the retention policy set for the job. If Veeam Backup & Replication detects an outdated restore point, it removes this point from the backup chain.
Reverse Incremental Backup

As a result, the most recent restore point in the backup chain is always a full backup, and it gets updated after every successful backup job session.

The reverse incremental backup method enables you to immediately restore a VM to the most recent state without extra processing because the most recent restore point is a full backup file. If you need to restore a VM to a particular point in time, Veeam Backup & Replication applies the required VRB files to the VBK file to get to the required restore point.

To use the reverse incremental backup method, you must select the Reverse incremental option in the backup job settings.

Reverse Incremental Backup

 

Active and Synthetic Full Backups

To let you get the most out of incremental backup, Veeam Backup & Replication lets you create active full backups and schedule creation of synthetic full backups on specific days.

In This Section
  • Active Full Backup
  • Synthetic Full Backup
  • Transforming Incremental Backup Chains into Reverse Incremental Backup Chains
  • Switching Between Backup Methods

 

Active Full Backup

In some cases, you need to regularly create a full backup. For example, your corporate backup policy may require that you create a full backup on weekend and run incremental backup on work days. To let you conform to these requirements, Veeam Backup & Replication offers the ability to periodically perform active full backups.

The active full backup produces a full backup of a VM, just as if you run the backup job for the first time. Veeam Backup & Replication retrieves data for the whole VM from the source, compresses and deduplicates it and stores it to the full backup file — VBK.

The active full backup resets the chain of increments: all subsequent increments use the latest active full backup as a new starting point. A previously used full backup file remains on disk until it is automatically deleted according to the backup retention policy.

Active Full Backup

You can create active full backups manually or schedule a backup job to create active full backups with a certain periodicity.
  • To create an active full backup manually, use the Active Full command from the shortcut menu of a corresponding backup job.
  • To schedule active full backups, specify scheduling settings in the Advanced section of a corresponding backup job. You can schedule active full backups to run weekly, for example, every Saturday, or monthly, for example, every fourth Sunday of a month.

 

Synthetic Full Backup

In some situations, running active full backups periodically may not be an option. Full backups are very resource-intensive and consume considerable amount of network bandwidth. As an alternative, you can create synthetic full backups.

In terms of data, the synthetic full backup is identical to a regular full backup. The synthetic full backup is a .vbk file that contains data of the whole VM. The difference between these two backup types lies in the way how VM data is retrieved:
  • When you perform full backup, Veeam Backup & Replication retrieves VM data from the source datastore (volume) where the VM resides, compresses and deduplicates it and writes it to the VBK file in the backup repository.
  • When you perform synthetic full backup, Veeam Backup & Replication does not retrieve VM data from the source datastore (volume). Instead, it “synthesizes” a full backup from data you already have in the backup repository. Veeam Backup & Replication accesses the previous full backup file and a chain of subsequent increments in the backup repository, consolidates VM data from these files and writes consolidated data into a new full backup file. As a result, the created synthetic full backup file contains the same data you would have if you created a full backup in a regular manner.
Veeam Backup & Replication treats a synthetic full backup as a regular full backup. As well as any other full backup, the synthetic full backup resets the chain of increments. All subsequent increments use the created synthetic full backup as a new starting point. A previously used full backup file remains on disk until it is automatically deleted according to the backup retention policy.

The synthetic full backup has a number of advantages:
  • The synthetic full backup does not use network resources: it is created from backup files you already have on disk.
  • The synthetic full backup imposes less load on the production environment: it is created right in the backup repository.
With Veeam Backup & Replication, you can schedule creation of synthetic full backups on specific days.

 

How Synthetic Full Backup Works

To create a synthetic full backup, Veeam Backup & Replication performs the following steps:
  1. On the day when synthetic full backup is scheduled, Veeam Backup & Replication triggers a new backup job session. During this session, Veeam Backup & Replication first performs incremental backup in a regular manner and adds a new incremental restore point to the backup chain.
VM data for this incremental restore point is retrieved from the production storage. Incremental backup helps Veeam Backup & Replication ensure that the synthetic full backup scheduled on this day includes the latest changes of the source VM in the production environment.
How Synthetic Full Backup Works 
  1. At the end of the backup job session, the Veeam Data Mover Service in the backup repository builds a new synthetic full backup using restore points that are already available in the backup chain, including the newly created incremental restore point.
How Synthetic Full Backup Works 
  1. When the synthetic full backup is created, the Veeam Data Mover Service deletes the incremental restore point created at the beginning of the job session.
As a result, you have a backup chain that consists of a full backup, set of incremental restore points and synthetic full backup.

How Synthetic Full Backup Works 
  1. Every next job session will create a new incremental restore point starting from the synthetic full backup until the day on which synthetic full backup is scheduled. On this day, Veeam Backup & Replication will create a new synthetic full backup.
How Synthetic Full Backup Works 
Veeam Backup & Replication automatically triggers a backup job session to create a synthetic full backup, even if a regular backup job session is not scheduled on this day. If a regular backup job is scheduled together with a synthetic full backup, Veeam Backup & Replication will produce only one backup file — a synthetic full backup that will reflect the latest state of the source VM. An incremental restore point that should have been created by the backup job schedule will not be added to the backup chain.

Veeam Backup & Replication creates a synthetic full backup only once a day on which it is scheduled. If you run the backup job again on the same day, Veeam Backup & Replication will perform incremental backup in a regular manner.

 

Transforming Incremental Backup Chains into Reverse Incremental Backup Chains

If you select to create synthetic full backups, you can additionally choose to transform a previous forward incremental backup chain into a reverse incremental backup chain. In this case, Veeam Backup & Replication will transform the latest backup chain consisting of the .vbk and .vib files into reverse incremental backups - .vrb files.

The transform option lets you dramatically reduce the amount of space required to store backups. Instead of two full backups — the regular full backup and the synthetic full backup — you will have only one synthetic full backup on disk. Note, however, that the transform process takes more time than simply creating a periodic synthetic full backup.

For example, you have configured a backup job to perform daily forward incremental backups and scheduled synthetic fulls on Thursday. Additionally, you have selected to transform the incremental backup chain into the reverse incremental backup sequence. The backup job starts on Sunday. In this case, Veeam Backup & Replication will perform backup in the following way:
  1. On Sunday, Veeam Backup & Replication will create a full backup; Monday through Wednesday Veeam Backup & Replication will create incremental backups and add them to the backup chain.
  2. On Thursday, Veeam Backup & Replication will first create an incremental backup in a regular manner and add it to the backup chain.
  3. After that, Veeam Backup & Replication will transform the incremental backup chain into the reverse incremental chain. As a result, you have a full backup “created” on Thursday and a set of reversed increments Sunday through Wednesday.
  4. When you run the backup job next time, Veeam Backup & Replication will add a new incremental backup to the chain; the synthetic full backup will be used as a starting point.
Transforming Incremental Backup Chains into Reverse Incremental Backup Chains

Veeam Backup & Replication always transforms only the latest incremental backup chain. For example, you have a backup chain that consists of one full backup file and set of increments. In the middle of the chain, you create an active full backup. When you run a transformation task, Veeam Backup & Replication will transform the most recent active full backup plus increments that follow it. All backups that precede the active full backup will stay intact.

Transforming Incremental Backup Chains into Reverse Incremental Backup Chains Note:
The transform process is accounted for as an active backup repository task. Make sure you properly plan use of backup repository resources when you schedule backup jobs.

 

Switching Between Backup Methods

With Veeam Backup & Replication, you can easily switch between backup methods.

Veeam Backup & Replication will not transform the previously created chain. Instead, it will create a new chain next to the existing one in the following manner:
  • If you switch from the reverse incremental method to the forward incremental method, Veeam Backup & Replication will create a set of incremental backups next to the reverse incremental chain. The full backup in the reverse incremental chain will be used as a starting point for produced increments.
  • If you switch from the forward incremental method to the reverse incremental method, Veeam Backup & Replication will first create a full backup next to the incremental backup chain. At every new job cycle, Veeam Backup & Replication will transform this full backup and add reverse incremental backups to the chain.

 

Retention Policy

Every successful run of a job creates a new restore point that lets you return your data to an earlier point in time. When you define retention policy, you specify how many restore points you want to keep and thus how ‘far’ you want to be able to roll back. Once the specified number is exceeded, the earliest restore point will be automatically removed. So if the retention policy is set to three and you already have three restore points, the fourth successful run of a job will delete the restore point created at the first job run.

Retention Policy Note:
When the allowed number of restore points in the backup chain is exceeded, Veeam Backup & Replication deletes the whole backup file, not separate VMs from it.

Veeam Backup & Replication handles restore points in different ways for forward forever-incremental, incremental and reverse incremental backup chains.

In This Section
  • Retention Policy for Forever Forward Incremental Backup
  • Retention for Forward Incremental Backup
  • Retention for Reverse Incremental Backup
  • Retention Policy for Deleted VMs
  • Removing Restore Points from the Backup Chain

 

Retention Policy for Forever Forward Incremental Backup

If the number of restore points in forever forward incremental backup chains exceeds the retention policy settings, Veeam Backup & Replication transforms the backup chain to make room for the most recent restore point. The transformation process is performed in the following way:

1. Veeam Backup & Replication adds a new restore point to the backup chain and detects that the number of allowed restore points is exceeded.

Veeam Backup & Replication re-builds the full backup file to include changes of the incremental backup following the full backup. To do this, Veeam Backup & Replication injects data blocks from the first incremental backup in the chain into the full backup. As a result, the full backup ‘moves’ one step forward in the backup chain.

Retention Policy for Forever Forward Incremental Backup  

2. The first incremental backup is removed from the backup chain as redundant. Its data has already been injected into the full backup and the full backup file contains the same data as this incremental restore point.

Retention Policy for Forever Forward Incremental Backup  

For example, you want to keep 7 restore points in the backup chain. The backup job starts on Sunday and runs daily. In this case, Veeam Backup & Replication will create the backup chain in the following way:
  1. During the first backup job session on Sunday, Veeam Backup & Replication creates the first restore point — a full backup.
  2. Monday through Saturday Veeam Backup & Replication adds six incremental backups to the chain.
Retention Policy for Forever Forward Incremental Backup  
  1. The next Sunday, Veeam Backup & Replication adds a new incremental backup to the backup chain.
  2. Veeam Backup & Replication detects that the number of allowed restore points is exceeded, and starts the transform process:
  1. Veeam Backup & Replication merges data blocks from the incremental backup copied on Monday into the full backup copied on Sunday. This way, the full backup file ‘moves’ one step forward — from Sunday to Monday.
Retention Policy for Forever Forward Incremental Backup  
  1. The incremental backup copied on Monday becomes redundant and is removed from the chain.
Retention Policy for Forever Forward Incremental Backup  
As a result, you have a chain of a full backup as of Monday and six incremental backups Tuesday through Sunday.

 

Retention for Forward Incremental Backup

To be able to restore from a forward incremental backup, you need to have a full backup and a chain of subsequent increments on disk. If you delete a full backup, the whole chain of increments will become useless. In a similar manner, if you delete any increment before the restore point to which you want to roll back, you won’t be able to restore your data (since later increments depend on earlier increments).

For this reason, if you select forward incremental backup, in some days there will be more restore points on disk than specified by your retention policy. Veeam Backup & Replication will remove the full backup chain only after the last increment in the chain meets your retention policy (which will happen once the retention policy reaches the next full backup).

For example, the retention policy is set to three restore points. A full backup is performed on Sunday, incremental backups are performed Monday through Saturday and a synthetic full backup is scheduled on Thursday. Although the retention policy is already breached on Wednesday, the full backup is not deleted because without it the chain of increments would be useless, leaving you without any restore point at all.

Veeam Backup & Replication will wait for the next full backup and two increments to be created, and only then delete the whole previous chain consisting of the full backup and increment, which will happen on Saturday.

Retention for Forward Incremental Backup

 

Retention for Reverse Incremental Backup

In case of reverse incremental backup, Veeam Backup & Replication immediately deletes the earliest reverse increment as soon as it meets the retention policy. For example, if the retention policy is set to three restore points, two latest reverse increments and a full backup will be retained.

Retention for Reverse Incremental Backup

 

Retention Policy for Deleted VMs

In some situations, after you configure and run backup jobs in Veeam Backup & Replication, you may want to change something in your virtual environment or even in your backup strategy. For example, you may remove some VMs from the virtual infrastructure or move them to another location. You may also exclude some VMs from jobs that have already been run for some time.

By default, when you remove a VM protected by Veeam Backup & Replication from the virtual infrastructure or exclude it from a job, its backup files still remain in the backup repository. To avoid keeping redundant data on disk, you can select to control retention policy for deleted VMs.

Retention Policy for Deleted VMs

The retention policy for deleted VMs is an option in the backup job settings. To use this option, you need to select the Remove deleted VMs data after days check box and specify the desired period of time for which data for deleted VMs must be retained in the backup repository.

With this option enabled, Veeam Backup & Replication will check the list of VMs included in the job when a job starts. If a VM is no longer available, for example, it was deleted or moved to another location, Veeam Backup & Replication will keep its data in the backup file for the specified period only. As soon as the specified retention period is over, data of the deleted VM will be removed from backup files in the backup repository.

Retention Policy for Deleted VMs Important!
When Veeam Backup & Replication removes data for deleted VMs, it does not free up space in the backup repository. It marks the space as available to be overwritten, and this space is overwritten during subsequent job sessions or the backup file compact operation.

Limitations for Retention Policy for Deleted VMs
Retention policy for deleted VMs is applied only to reverse incremental backup chains and forward incremental backup chains for which synthetic full backups with subsequent transform is enabled.

 

Removing Restore Points from the Backup Chain

To keep up with the retention policy, Veeam Backup & Replication deletes the whole backup file from the backup chain, not data for separate VMs from the backup file. For this reason, in some situations a certain VM may have fewer restore points in the backup chain than it is specified in the retention policy settings. This can happen if a backup job processes a number of VMs or VM containers and some VMs or VM containers fail to be processed in some job sessions.

Removing Restore Points from Reverse Incremental Chains
In case of a reverse incremental backup chain, Veeam Backup & Replication immediately deletes a redundant restore point when the allowed number of restore points is exceeded.

For example, a backup job processes two VMs: VM1 and VM2. According to the retention policy settings, the backup chain must contain 5 restore points. The backup job has already had 5 job sessions and VMs have been processed in the following way:

VM1 has been successfully backed up 5 times and has 5 restore points
  • VM2 has failed to be processed in two job sessions and therefore has 3 restore points
Removing Restore Points from the Backup Chain

After that, Veeam Backup & Replication runs a new backup job session in which VM1 and VM2 are successfully processed. When a new restore point is added to the chain, Veeam Backup & Replication removes the earliest restore point because the number of restore points in the backup chain has exceeded 5. As a result, you will have 5 restore points for VM1 and 4 restore points for VM2.

Removing Restore Points from the Backup Chain

Removing Restore Points from Forward Incremental Chains
In case of a forward incremental backup chain, Veeam Backup & Replication does not remove a restore point immediately. Instead, Veeam Backup & Replication waits for a new full backup (synthetic or active) to be created and a new backup chain to be started. As soon as the last incremental restore point in the "old" backup chain is marked as redundant, Veeam Backup & Replication removes the whole "old" backup chain from the backup repository.

For example, a backup job processes two VMs: VM1 and VM2. According to the retention policy settings, the backup chain must contain 3 restore points. The backup job has already had 5 job sessions and VMs have been processed in the following way:
  • VM1 has been successfully backed up 3 times and has 3 restore points
  • VM2 has failed to be processed in 2 job sessions and has 1 valid restore point
When a new restore point is added to the backup chain, Veeam Backup & Replication will not remove the earliest restore point from the backup chain. Veeam Backup & Replication will wait until a new full backup and 2 incremental backups are added to the backup chain. After that, the whole outdated backup chain will be removed from the backup repository. Restore points in the "new" backup chain, at the same time, may contain data for both VMs or for one VM only: Veeam Backup & Replication regards backup files as restore points, not separate VMs in these files.


Removing Restore Points from the Backup Chain

Per-VM Backup Files

By default, the backup job writes VM data to the backup repository in one write stream and stores data of all VMs to the same backup file. Such behavior can cause problems if the target storage device is able to write data in multiple streams simultaneously. In this situation, the backup repository may become a bottleneck in the data flow though its resources will not be used to the full.

Per-VM Backup Files

You can instruct Veeam Backup & Replication to create per-VM backup files in the backup repository. In this case, the job will use a separate write stream for every VM in the job and store its data to a separate backup file. As a result, resources of the storage device will be used more efficiently, and the job performance may increase.

Per-VM Backup Files

To create per-VM backup files, you must enable the Use per-VM backup files option at the level of the backup repository. It is recommended that you enable this option for deduplicating storage appliances that support multiple write streams. The option is also enabled for scale-out backup repositories by default.

Per-VM Backup Files 

If you decide to create separate backup files for VMs in the job, make sure that you enable parallel data processing. If parallel data processing is disabled, Veeam Backup & Replication will process VMs and VM disks sequentially, one by one. You should also balance the number of tasks on backup proxies and backup repository to avoid the situation when some backup infrastructure resources remain idle while others are overloaded. It is recommended that you use all available slots of the backup repository.

To do this, you must disable the Limit maximum concurrent tasks to N option in the backup repository settings.

Per-VM Backup Files

Per-VM Backup Files Note:
In case of per-VM backup chains, synthetic operations (synthetic full backup, backup files merge and transform) work in parallel for every VM in the backup. The number of parallel operations is limited by the number of concurrent tasks that can be performed on the backup repository.

Enabling Per-VM Backup Files Option for Existing Backup Repositories
You can enable or disable the Use per-VM backup files option for existing backup repositories to which backup jobs are already targeted. The new setting will not have any effect on previously created backup files in the backup repository. It will affect new backup files created after the setting is changed.

Veeam Backup & Replication applies the new setting starting from the next active full backup. You can create an active full backup manually or wait for Veeam Backup & Replication to automatically create active full backup (if active full backups are scheduled). Synthetic full backups do not affect the Use per-VM backup files setting.

Limitations for Per-VM Backup Files Option
The Use per-VM backup files option cannot be enabled for backup repositories with rotated drives.

 

Retention for Per-VM Backup Files

If you enable the Use per-VM backup files option for the backup repository, Veeam Backup & Replication creates a separate backup chain for every VM added to the job. Backup files are stored together in the folder of the backup job in the backup repository. The job produces one metadata file. This file stores information about all created backup files and backup chains.

Veeam Backup & Replication regards all backup files that are created during one backup job session as one restore point. When Veeam Backup & Replication needs to remove earlier restore points by retention policy, it removes backup files for all VMs that were created during one job session.

For example, you have added 3 VMs to the job, set the retention setting to 5 restore points and run the job 5 times. The job will produce 15 backup files, 5 per each VM in the job. On the 6th job session, the job will remove from the backup chain 3 backup files — the earliest restore points for every VM.

Retention for Per-VM Backup Files

If the job backs up some VMs during the job session and does not manage to back up others, Veeam Backup & Replication will still regard that the restore point is valid. When the earliest restore point gets outdated, Veeam Backup & Replication will remove backup files for all VMs at once, even though backup chains for some VMs may contain fewer backup files than you expect.

The rules of restore points deletion for regular backup chains also apply to per-VM backup chains.

For example, you have added 3 VMs to the job and set retention policy to 5. The backup job session ran in the following way:
  1. During the first three job sessions, Veeam Backup & Replication backed up all VMs.
  2. During the 4th and 5th job sessions, VM1 and VM2 were successfully backed up, and VM3 failed.
During the 6th job session, Veeam Backup & Replication will delete the earliest restore point for all VMs. As a result, the VM1 and VM2 will have 5 restore points and VM3 will have 3 restore points.

Retention for Per-VM Backup Files

 

Changed Block Tracking

When Veeam Backup & Replication performs incremental backup, it needs to know what data blocks have changed since the previous job run. To keep track of changing data blocks, Veeam & Backup & Replication uses its proprietary Hyper-V changed block tracking mechanism (CBT).

The CBT mechanism is implemented as a file system filter driver. Veeam CBT driver is installed on every Hyper-V host that is added to the list of managed servers in Veeam Backup & Replication. The driver is activated when the host is first addressed by a job with enabled CBT.

The Veeam CBT driver keeps track of changing data blocks in virtual disks. Information on data blocks that have changed is registered in special .ctp files. When a job is run, Veeam Backup & Replication uses .ctp files to learn what blocks of data have changed since the last run of this particular job, and copies only changed data blocks from the disk image.

Changed Block Tracking 

.ctp files are stored in the C:\ProgramData\Veeam\CtpStore folder on standalone Hyper-V hosts or on every node of the Hyper-V cluster. The CtpStore folder contains a set of subfolders — one for every processed VM, in which the following files are stored:
  • .ctp files. These files are used by the Veeam CBT driver to keep track of changed data blocks. For every VHD/VHDX or AVHD/AVHDX file of a VM, there is a separate .ctp file.
  • notes.txt file. This file contains basic information about the VM such as VM name and ID, and describes for which .vhd files changed block tracking is enabled.
If a Hyper-V VM is registered as a cluster resource, the Veeam CBT driver operates on all cluster nodes that have access to the VM disks on the CSV. When a backup job is run, Veeam Backup & Replication copies .ctp files to the temporary folder on the backup proxy used by the backup job:
  • If backup is performed in the on-host backup mode, .ctp files are copied to the Hyper-V host performing the role of the on-host backup proxy.
  • If backup is performed in the off-host backup mode, .ctp files are copied to the off-host backup proxy.
Use of CBT increases the speed and efficiency of block-level incremental backups. CBT is enabled by default. You can disable it either at the host level or at the job level for troubleshooting purposes. Note that if you choose to run incremental jobs with CBT disabled, the backup window may increase dramatically, as Veeam Backup & Replication will read all of VM data to detect what blocks have changed since the last job run.

Changed Block Tracking Important!
If you process VMs on a Microsoft Hyper-V cluster, make sure that the cluster nodes are online. If cluster nodes are in the maintenance mode, have the cluster service stopped, are powered off or not accessible, CBT will not work.

CBT Reset
In some cases, CBT data may get corrupted — as a result, Veeam Backup & Replication will fail to process VMs with changed block tracking. To reset CBT data for individual VMs or specific VHD/VHDX files, you can use the Reset-HvVmChangeTracking PowerShell cmdlet.

Keep in mind that CBT data is reset when you perform product upgrade. When you run a backup job for the first time after upgrade, Veeam Backup & Replication will not use changed block tracking. Instead, it will scan the VM image to learn what data blocks have changed.

 

Data Compression and Deduplication

Veeam Backup & Replication provides mechanisms of data compression and deduplication. Data compression and deduplication let you decrease traffic going over the network and disk space required for storing backup files and VM replicas.

Data Compression
Data compression decreases the size of created backups but affects duration of the backup procedure. Veeam Backup & Replication allows you to select one of the following compression levels:
  • None compression level is recommended if you use plan to store backup files and VM replica files on storage devices that support hardware compression and deduplication.
  • Dedupe-friendly is an optimized compression level for very low CPU usage. You can select this compression level if you want to decrease the load on the backup proxy.
  • Optimal is the recommended compression level. It provides the best ratio between size of the backup file and time of the backup procedure.
  • High compression level provides additional 10% compression ratio over the Optimal level at the cost of about 10x higher CPU usage.
  • Extreme compression provides the smallest size of the backup file but reduces the backup performance. We recommend that you run backup proxies on computers with modern multi-core CPUs (6 cores recommended) if you intend to use the extreme compression level.
Deduplication
You can enable data deduplication if you add to the backup or replication job several VMs that have great amount of free space on their logical disks or VMs that have similar data blocks — for example, VMs that were created from the same template. Veeam Backup & Replication does not store zero byte blocks or space that has been pre-allocated but not used. With data deduplication, identical blocks or blocks of free space are eliminated, which decreases the size of the created backup file.

Depending on the type of storage you select as a backup target, Veeam Backup & Replication uses data blocks of different size to process VMs, which optimizes the size of a backup file and job performance. You can choose one of the following storage optimization options:
  • The Local target (16 TB + backup files) option is recommended for backup jobs that can produce very large full backup files — larger than 16 TB. With this option selected, Veeam Backup & Replication uses data block size of 4096 KB.
If you select to use data blocks of small size to dedupicate a large backup file, the backup file will be cut into a great number of data blocks. As a result, Veeam Backup & Replication will produce a very large deduplication metadata table which can potentially overgrow memory and CPU resources of your backup repository. For backup files over 16 TB, it is recommended to choose the Local target (16 TB + backup size) option. 

With this option selected, Veeam Backup & Replication will use data blocks of 4 MB. Large data blocks produce a smaller metadata table that requires less memory and CPU resources to process. Note, however, that this storage optimization option will provide the lowest deduplication ratio and the largest size of incremental backup files.

Data Compression and Deduplication Note:
If you upgrade to Veeam Backup & Replication 9.0 from the previous product version, this option will be displayed as Local target (legacy 8MB block size) in the list and will still use blocks size of 8 MB. It is recommended that you switch to an option that uses a smaller block size and create an active full backup to apply the new setting.
  • The Local target option is recommended for backup to SAN, DAS or local storage. With this option selected, Veeam Backup & Replication uses data block size of 1024 KB.
The SAN identifies larger blocks of data and therefore can process large amounts of data at a time. This option provides the fastest backup job performance but reduces the deduplication ratio, because with larger data blocks it is less likely to find identical blocks.
  • The LAN target option is recommended for backup to NAS and onsite backup. With this option selected, Veeam Backup & Replication uses data block size of 512 KB. This option provides a better deduplication ratio and reduces the size of a backup file because of reduced data block sizes.
  • The WAN target option is recommended if you are planning to use WAN for offsite backup. With this option selected, Veeam Backup & Replication uses data block size of 256 KB. This results in the maximum deduplication ratio and the smallest size of backup files, allowing you to reduce the amount of traffic over WAN.
Changing Data Compression Settings
You can change data compression settings for existing backup jobs. New settings will not have any effect on previously created backup files in the backup chain. They will be applied to new backup files created after the settings were changed. 

Compression settings are changed on the fly. You do not need to create a new full backup to use new settings — Veeam Backup & Replication will automatically apply the new compression level to newly created backup files.

However, if you use the reverse incremental backup method, the newly created backup files will contain a mixture of data blocks compressed at different levels. For example, you have a backup job that uses the reverse incremental backup method and the Optimal level of compression. After several job sessions, you change the compression level to High. In the reverse incremental backup chains, the full backup file is rebuilt with every job session to include new data blocks. As a result, the full backup file will contain a mixture of data blocks: data blocks compressed at the Optimal level and data blocks compressed at the High level.

If you want the newly created backup file to contain data blocks compressed at one level, you can create an active full backup. Veeam Backup & Replication will retrieve data for the whole VM image from the production infrastructure and compress it at the new compression level. All subsequent backup files in the backup chain will also use the new compression level.

Changing Data Deduplication Settings
You can change data deduplication settings for existing backup jobs. New settings will not have any effect on previously created backup files in the backup chain. They will be applied to new backup files created after the settings were changed.

Backup Jobs
To apply new deduplication settings in backup jobs, you must create an active full backup after you change deduplication settings. Veeam Backup & Replication will use the new block size for the active full backup and subsequent backup files in the backup chain.

Backup Copy Jobs
To change data block size for a backup copy job, you must perform the following actions:
  1. Change data block size in settings of the initial backup job.
  2. Create an active full backup with the initial backup job.
  3. Create an active full backup with the backup copy job.

 

Data Exclusion

When you configure a backup or replication job, you can define what data you want to back up and replicate and exclude data that you do not need. Data exclusion helps reduce the size of the VM backup or replica and decrease the load on the network.

You can exclude data at the VM level and at the VM guest OS level.

At the VM level:
  • VMs added as part of the container
  • VM disks
At the VM guest OS level:
  • Swap files on the VM guest OS
  • Deleted file blocks on the VM guest OS (BitLooker)
  • Files and folders on the VM guest OS

 

VMs and VM Disks

When you configure a backup or replication job, you can exclude the following objects from processing:
  • VMs added as a part of a VM container
  • Individual VM disks
If you want to back up or replicate a VM container that holds several VMs but want to skip some VMs, you can exclude specific VMs from the job processing. This option will help you reduce the size of the resulting backup or replica and increase the job performance.

You can define which VMs you want to skip at the Virtual Machines step of the backup or replication job wizard.

VMs and VM Disks

You can choose what VM disks you want to back up or replicate:
For example, you may want to back up or replicate only the system disk instead of creating a backup or replica of a full VM. VM disks exclusion reduces the size of the backup or replica.

You can define which VM disks you want to back up or replicate at the Virtual Machines step of the backup or replication job wizard. You can specify disk processing settings granularly for every VM in the job or for the whole VM container. In the latter case, Veeam Backup & Replication will apply the configured rule to all VMs in this container. 

VMs and VM Disks

 

Deleted File Blocks (BitLooker)

By default, Veeam Backup & Replication does not copy "dirty" data blocks (blocks that are marked as deleted on the VM guest OS) to the target location. This option lets you reduce the size of the VM backup or replica and increase the job performance.

If you do not want to exclude deleted file blocks from backups or replicas, you can disable the Exclude deleted file blocks option in the backup or replication job settings.

Deleted File Blocks (BitLooker) Note:
If you enable or disable the Exclude deleted file blocks setting for the existing job, Veeam Backup & Replication will apply the new setting from the next job session.

Deleted File Blocks (BitLooker)

With this option enabled, Veeam Backup & Replication performs the following operations during the job session:
  1. Veeam Backup & Replication accesses the MFT file on the VM guest OS to identify deleted file blocks, and zeros out these blocks.
  2. Veeam Backup & Replication processes and transports data blocks of the VM image in the following manner:
  • If a data block of the VM image contains only the deleted file blocks, Veeam Backup & Replication does not read this data block from the source volume.
  • If a data block of the VM image contains zeroed out blocks and other data, Veeam Backup & Replication copies this block to the target. Due to data compression, data blocks that are marked as deleted are compressed, and the size of the resulting backup or replica file reduces.
Deleted File Blocks (BitLooker)

Limitations for Deleted File Blocks Exclusion
Veeam Backup & Replication can exclude deleted file blocks only on the VM guest OS with Microsoft NTFS.

Swap Files

You can instruct Veeam Backup & Replication to exclude pagefile.sys and hiberfil.sys files from backups or replicas of Microsoft Windows VMs.
  • hiberfil.sys is a system file created by the OS for correct work of the hibernate mode.
  • pagefile.sys is a swap file. Swap files are dynamic in nature and can change intensively between job sessions, even if a VM itself does not change much.
To exclude these files, you must enable the Exclude swap file blocks option in the job settings.

Veeam Backup & Replication will identify data blocks of these files and exclude them from processing. As a result, the size of incremental backups and replicas will be smaller.

Swap Files

When you exclude pagefile.sys and hiberfil.sys files, Veeam Backup & Replication performs the following operations during the job session:
  1. Veeam Backup & Replication accesses the MFT file on the VM guest OS to identify data blocks of pagefile.sys and hiberfil.sys files and zeros them out.
  2. Veeam Backup & Replication processes and transports data blocks of the VM image in the following manner:
  • If a data block of the VM image contains only blocks of these files, Veeam Backup & Replication does not copy this data block to the target.
  • If a data block of the VM image contains blocks of these files and other data, Veeam Backup & Replication copies this block to the target.
Swap Files

Limitations for Swap Files Exclusion
Veeam Backup & Replication can exclude blocks of pagefile.sys and hiberfil.sys files only on the VM guest OS with Microsoft Windows NTFS.

VM Guest OS Files

If you do not want to back up or replicate some files and folders on the VM guest OS, you can exclude them from the backup or replica. Files exclusion reduces the size of the backup or replica but may affect the job performance.

You can specify file exclusion settings granularly for every VM in the job or for the whole VM container. In the latter case, Veeam Backup & Replication will apply the configured rule to all VMs in this container.

To define which VM guest OS files must and must not be processed, you can use the following options:
  • Disable file exclusion. Veeam Backup & Replication will back up or replicate the whole content of the VM guest file system.
  • Exclude specific files and folders from the backup or replica. Veeam Backup & Replication will back up or replicate all files and folders except the specified ones.
  • Include only specific files and folders in the backup or replica. Veeam Backup & Replication will back up or replicate only the specified files and folders.
To form a list of exclusions or inclusions, you can use the following methods:
  • Specify a full path to a folder on the VM guest OS, for example, C:\Documents\.
  • Specify a full path to a file on the VM guest OS, for example: C:\Documents\MyReport.docx.
If a path is not full, Veeam Backup & Replication will expand it relatively the root directory on the computer volume and attempt to detect such files on all computer volumes. For example, you have C, D and E disks on the VM. In the list of exclusions, you specify Document.docx. Veeam Backup & Replication will scan the whole file system and exclude the following files (if any): C:\Document.docx, D:\Document.docx, E:\Document.docx. If there is a C:\MyDocuments\Document.docx file, it will not be excluded — this file is not located in the root directory.
  • Use environmental variables, for example, %TEMP%, %windir%. Environment variables must be defined for the user account that you use to connect to the VM guest OS and under which the runtime process is started. For example, you connect to the VM guest OS under the Administrator account. If you want to use the %windir% variable in the list of exclusions or inclusions, you must make sure that the %windir% variable is added to the list of user variables for Administrator on the VM guest OS.
  • Use file masks. You can use the following characters for masks:
  • (*) — a substitution for one or more characters in the file name or path. Can be used for any sequence of characters (including no characters). For example, *.pdf.
  • (?) – a substitution of one character in the file name or path. For example, repor?.pdf
  • (;) – mask separator, for example, report.*;reports.*.
In the table below, mask stands for any sequence of characters.
Mask formatAffects paths/files
*mask*All paths that contain the given sequence.
maskIf the asterisk character (*) is not specified at the beginning of the mask, the mask will be applied to all volumes on the VM guest OS, and Veeam Backup & Replication will include/exclude files or folders in the root folder on the volume: A:\mask, B:\mask, …, Z:\mask.
mask*If the asterisk character (*) is not specified at the beginning of the mask, the mask will be applied to all volumes on the VM guest OS, and Veeam Backup & Replication will include/exclude files and folders in the root folder on the volume: A:\mask*, B:\mask*, …, Z:\mask*.
:\*mask*All paths on the specified volume that contain the given sequence.
*mask1*;*mask2*;*mask3*All paths that contain at least one of the given character sequences: *mask1* or *mask2* or *mask3*.
VM Guest OS Files Important!
Be careful when using masks with double wildcard characters. If you specify masks of such type, Veeam Backup & Replication will exclude all files and paths that contain the given mask. For example, if you specify the *.doc* mask, Veeam Backup & Replication will exclude files like MyReport.docx, Report.doc.txt and so on.
Mind the following:
  • If you use file masks for file exclusion, Veeam Backup & Replication will need to scan the VM guest file system, and the time of VM disk processing will increase.
  • The number of entries in the list of exclusions or inclusions must not exceed a few hundreds. The number of entries in the list influences the job performance — the more files are included or excuded from the backup or replica, the more time Veeam Backup & Replication requires to process these files.
  • It is recommended that you do not exclude system files without the necessity. Veeam Backup & Replication does not perform any checks to verify the VM image integrity.
  • Exclusion of small files (less than 2 KB in size) is ineffective and will not reduce the size of the backup or replica significantly.
VM Guest OS Files
Requirements and Limitations for VM Guest Files Exclusion
VM guest OS files exclusion has the following limitations:
  • File exclusion works only on Microsoft Windows NTFS.
  • File exclusion is available in Enterprise and Enterprise Plus Editions of Veeam Backup & Replication.
  • To exclude VM guest OS files, Veeam Backup & Replication must be able to deploy the runtime process inside the VM. For this reason, the VM must be running and accessible by an IP address, and credentials for application-aware processing must be valid.
  • Veeam Backup & Replication supports both basic and dynamic disks. Volumes on the dynamic disks must not be split — spanned, striped and other types of split volumes are not supported.
  • It is not recommended that you use VM guest files exclusion for Microsoft Windows Data Deduplication-Enabled Volumes. If you decide to use VM guest files exclusion for such volumes and set up a list of inclusions, you must add the System Volume Information folder to the list of inclusions.
How VM Guest OS File Exclusion Works
When you exclude VM guest OS files from the backup or replica, Veeam Backup & Replication performs the following operations:
  1. Veeam Backup & Replication checks the job settings to identify what VM guest OS files must be excluded.
  2. Veeam Backup & Replication opens the MFT file from the VM guest file system in the memory cache on the backup proxy, and marks data blocks of excluded files as deleted.
  3. When Veeam Backup & Replication copies VM data to the target, it reads data both from the VM snapshot and memory cache on the backup proxy. On the target, Veeam Backup & Replication creates a "merged" version of VM disks that do not contain excluded VM guest OS files. Due to data compression, data blocks that are marked as deleted are compressed, and the size of the resulting backup or replica file reduces.

VM Guest OS Files

During the job session with file exclude, Veeam Backup & Replication makes changes to processed VM disks at the NTFS level using the cache on the backup proxy. However, these changes are not visible to the CBT mechanism.

For this reason, Veeam Backup & Replication saves information about excluded data blocks in the backup file and replica metadata. During the next job session with use of CBT, Veeam Backup & Replication retrieves a list of data blocks that were excluded during the previous job session from the backup file or replica metadata and analyzes what data needs to be processed during the current job session. To do this, Veeam Backup & Replication regards the following data:
  • Data blocks that are marked as new with CBT
  • Data blocks that were excluded during the previous job session
  • Data blocks that must be excluded during the current job session

 

Transaction Consistency

When you back up or replicate a running VM, you need to quiesce, or ‘freeze’ the VM to bring its file system and application data to a consistent state. If the VM is not quiesced, Veeam Backup & Replication will produce a crash-consistent backup or replica. The crash consistent backup or replica does not preserve data integrity of open files and transactional applications on the VM. Restore from a crash-consistent backup or replica is essentially equivalent to booting the VM after it was manually reset.

A crash-consistent backup or replica may be sufficient for VMs that run applications with low quantity of transactions. If you process VMs with highly transactional applications, you should instruct Veeam Backup & Replication to quiesce the VM and create a transactionally consistent backup or replica. Restore from transactionally consistent backups or replicas guarantees safety of application data.

Veeam Backup & Replication offers two options for creating transactionally consistent backups and replicas:
  • Application-aware processing (based on Microsoft VSS). This option is recommended for VMs running applications that support Microsoft VSS.
  • Microsoft Hyper-V guest quiescence. This option is recommended for VMs running applications that do not support Microsoft VSS, for example, Linux VMs.

 

Microsoft Hyper-V Guest Quiescence

To create transactionally consistent backups and replicas for VMs that do not support Microsoft VSS (for example, Linux VMs), you must enable Microsoft Hyper-V guest quiescence for the job. In this case, Veeam Backup & Replication will use a native Microsoft Hyper-V approach to quiesce the VM. Microsoft Hyper-V guest quiescence helps freeze the file system and application data on the VM and create a stable shadow copy of the volume where VM data resides.

To quiesce the VM, Veeam Backup & Replication can use the following methods:
  • Online backup (Microsoft Hyper-V method)
  • Offline backup (Microsoft Hyper-V method)
  • Crash-consistent backup (Veeam method)
The quiescence method is selected in the following way:
  • If a VM meets all requirements for online backup, Veeam Backup & Replication will use the online backup method.
  • If a VM does not meet requirements for online backup, Veeam Backup & Replication will use the offline backup method. During offline backup a VM is suspended for a short period of time. If you do not want to suspend the VM, you can instruct Veeam Backup & Replication to create a crash-consistent backup instead of creating a transactionally consistent backup with the offline backup method.
Microsoft Hyper-V guest quiescence is enabled at the job level for all VMs added to the job. By default, this option is disabled.

Microsoft Hyper-V Guest Quiescence

Choice of Method for VM Quiescence

Application-aware processing is the recommended option for VMs running applications that support Microsoft VSS — Microsoft Exchange, Microsoft Active Directory and other. If you cannot use application-aware processing (for example, you cannot access the VM over the network and deploy Veeam's runtime process on it, or you want to process a Linux VM and want the backup or replica to be consistent at the application and file system level), you should enable Microsoft Hyper-V guest quiescence. Microsoft Hyper-V guest quiescence will put applications on the VM to a consistent state before the VM snapshot is created.

If you use Microsoft Hyper-V guest quiescence, Veeam Backup & Replication will quiesce the VM but will not perform application-specific actions required for proper backup and restore of VMs running highly transactional applications. Application-specific steps include the following tasks:
  • Applying application-specific settings to prepare applications for VSS-aware restore at the next VM startup
  • Truncating transaction logs after successful backup or replication.
Enabling Both Quiescence Options
You can enable both options for VM quiescence. Such scenario is recommended if you add Microsoft Windows and Linux VMs to the same job. In this case, all VMs will be processed in a transactionally consistent manner — either with application-aware processing or Microsoft Hyper-V guest quiescence.

In such scenario, Veeam Backup & Replication will process VMs in the job in the following way:
  1. Veeam Backup & Replication will first attempt to use application-aware processing to prepare VMs for backup or replication. If Veeam Backup & Replication manages to quiesce all VMs in the job with application-aware processing, it will not use Microsoft Hyper-V guest quiescence.
  2. If some VMs cannot be quiesced with application-aware processing or application-aware processing is disabled for some VMs in the job (the Disable application processing is set for VMs in the job settings), Veeam Backup & Replication will use Microsoft Hyper-V guest quiescence to prepare these VMs for backup or replication.
To enable both options:
  1. At the Storage step of the wizard (for backup) or Job Settings step of the wizard (for replication), click Advanced.
  2. On the Hyper-V tab of the Advanced Settings window, select Enable Hyper-V guest quiescence.
Choice of Method for VM Quiescence 
  1. At the Guest Processing step of the wizard, select the Enable application-aware processing check box.
Choice of Method for VM Quiescence 
  1. When configuring advanced option for individual VMs, select Try application processing, but ignore failures. You can also select the Disable application processing option for VMs that you want to process with Microsoft Hyper-V guest quiescence.
Choice of Method for VM Quiescence 
Choice of Method for VM Quiescence Note:
If you enable application-aware processing and Microsoft Hyper-V guest quiescence but do not select the Ignore application processing failures option, Veeam Backup & Replication only use only application-aware processing for the job. 

Guest Processing

If you back up or replicate running VMs, you can enable guest processing options. Guest processing options are advanced tasks that require Veeam Backup & Replication to communicate with the VM guest OS. Veeam Backup & Replication offers the following guest processing options:
  • Application-aware processing. You can create transactionally consistent backups and replicas of VMs running applications that support Microsoft VSS. Application-aware processing guarantees that you can restore VMs without data loss.
  • Pre-freeze and post-thaw scripts. You can use pre-freeze and post-thaw scripts to quiesce VMs running applications that do not support Microsoft VSS.
  • Transaction log truncation. You can set the backup or replication job to truncate transaction logs on the VM guest OS after the VM is successfully processed.
  • Transaction logs backup for Microsoft SQL Server and Oracle. You can set up the backup job to back up transaction logs from Microsoft SQL Server and Oracle VMs.
  • VM guest file system indexing. You can set up the backup job to create a catalog of files and folders on the VM guest OS. The catalog lets you search for VM guest OS files and 1-click restore in Veeam Backup Enterprise Manager.
VM guest file system indexing is optional. If you do not enable this option in the backup job settings, you will still be able to perform 1-click restore from the backup created with such backup job.
  • VM guest OS files exclusion. You can exclude/include individual files and folders from/to backup or replicas.

 

Runtime Coordination Process

To perform guest processing tasks, Veeam Backup & Replication does not deploy persistent agents inside VMs. Instead, it uses a runtime coordination process. The runtime process is non-persistent — it is deployed on every VM added to the job when the job starts and removed as soon as the job finishes. Use of the runtime process helps avoid agent-related drawbacks such as pre-installing, troubleshooting and updating.

Veeam Backup & Replication can deploy the runtime process on VMs in two ways:
  • For VMs running Microsoft Windows, the runtime process is deployed via guest interaction proxies.
  • For VMs running OSes other than Microsoft Windows, for example, Linux, the runtime process is deployed from the backup server.
The backup server or guest interaction proxy must have a LAN connection to the VM that will be processed.

Runtime Coordination Process Note:
If there are no guest interaction proxies or guest interaction proxies fail for some reason, Veeam Backup & Replication will deploy the runtime process on Microsoft Windows VMs from the backup server.

When you start a job with guest processing tasks enabled, Veeam Backup & Replication performs the following operations:
  1. Veeam Backup & Replication defines the machine(s) that will perform the guest interaction proxy role.
  2. Veeam Backup & Replication obtains IP addresses from Hyper-V Integration Services installed on VMs.
Veeam Backup & Replication deploys the runtime process on VMs:
  • [For Microsoft Windows VMs] The guest interaction proxy connects to VMs and deploys the runtime process on them.
  • [For VMs running other OSes] The backup server connects to VMs and deploys the runtime process on them.
  1. The job session proceeds as usual.
  2. When the job session completes, Veeam Backup & Replication deletes the runtime process on VMs.
Runtime Coordination Process

If a network connection breaks during the job session, Veeam Backup & Replication makes attempts to re-establish the connection:
  • If a network connection between the backup server/guest interaction proxy and VM guest OS breaks, Veeam Backup & Replication makes one attempt to reconnect.
  • If a network connection between the backup server and guest interaction proxy breaks, Veeam Backup & Replication makes 10 attempts to reconnect.
If attempts are unsuccessful, guest processing tasks fail. The job proceeds with the scenario defined in the job settings. For example, if you have instructed a backup job to try application processing but ignore failures, Veeam Backup & Replication will not perform guest processing tasks but will proceed with the VM backup.

Application-Aware Processing

To create transactionally consistent backups or replicas of VMs that run VSS-aware applications such as Microsoft Active Directory, Microsoft SQL Server, Microsoft Exchange or Oracle, you must enable application-aware processing for the job.

Application-aware processing is Veeam's proprietary technology based on Microsoft VSS. Microsoft VSS is responsible for quiescing applications on the VM and creating a consistent view of application data on the VM guest OS. Use of Microsoft VSS ensures that there are no unfinished database transactions or incomplete application files when Veeam Backup & Replication triggers the VM checkpoint and starts copying VM data to the target. For more information about Microsoft VSS, see https://technet.microsoft.com/en-us/library/cc785914(v=ws.10).aspx.

Application-aware processing is supported for Microsoft Windows 2003 SP2 and later. To use application-aware processing, you must have Hyper-V Integration Services and the latest updates installed on the VM guest OS.

Application-Aware Processing Note:
To process VMs running applications that do not support Microsoft VSS (for example, MySQL that does not have VSS writers), you can use Microsoft Hyper-V guest quiescence with pre-freeze and post-thaw scripts. For more information, see Microsoft Hyper-V Guest Quiescence and Pre-Freeze and Post-Thaw Scripts.

How Application-Aware Processing Works
If you enable application-aware processing for the job, Veeam Backup & Replication performs the following operation as a part of the backup or replication process:
  1. Veeam Backup & Replication deploys the runtime process on the VM and detects if the VM runs VSS-aware applications.
  2. Veeam Backup & Replication collects information about applications installed on VMs; this information is required for VSS-aware restore.
  3. Veeam Backup & Replication prepares applications for VSS-aware restore (VSS-aware restore is performed when the VM is started after you restore it from the backup or fail over to a VM replica).
  4. Microsoft VSS communicates with applications and quiesces I/O activities at a specific point in time.
  5. Microsoft Hyper-V VSS requestor triggers a VM VSS snapshot.
  6. Microsoft VSS resumes quiesced I/O activities on the VM guest OS.
  7. Veeam Backup & Replication triggers a snapshot for the volume on which the VM is located.
  8. The job session proceeds as usual.
  9. If you have instructed Veeam Backup & Replication to truncate transaction logs, Veeam Backup & Replication truncates transaction logs on the VM guest OS after the backup or replica are successfully created.

Application-Aware Processing

 

Pre-Freeze and Post-Thaw Scripts

If you back up or replicate VMs running applications that do not support Microsoft VSS, you can instruct Veeam Backup & Replication to run custom scripts for VMs. For example, the pre-freeze script may quiesce the file system and application data on the VM guest OS to bring the VM to a consistent state before Veeam Backup & Replication triggers a VM checkpoint. After the VM checkpoint is committed, the post-thaw script may bring the VM and applications to their initial state.

You can use pre-freeze and post-thaw scripts for the following types of jobs:
  • Backup job
  • Replication job
Pre-freeze and post-thaw scripts can be used for Microsoft Windows and Linux VMs.
  • For Microsoft Windows VMs, Veeam Backup & Replication supports scripts in the EXE, BAT and CMD file format.
  • For Linux VMs, Veeam Backup & Replication supports scripts in the SH file format.
Scripts must be created beforehand. You must specify paths to them in the job settings. Script execution settings can be configured per VM or per container, depending on the objects included in the job.
When the job starts, Veeam Backup & Replication uploads scripts to the VM guest OS and executes them.
  • Scripts for Microsoft Windows VMs are uploaded over the network.
  • Scripts for Linux VMs are uploaded over SSH.
The script is considered to be executed successfully if "0" is returned.

The default time period for script execution is 10 minutes. If the script fails to execute before the timeout expires, Veeam Backup & Replication displays an error message in the job session and error or warning messages issued during script execution.

Pre-Freeze and Post-Thaw Scripts

Limitations for Pre-Freeze and Post-Thaw Scripts
Veeam Backup & Replication has the following limitations for pre-freeze and post-thaw scripts:
  1. You cannot stop a job when the pre-freeze or post-thaw script is executed. If the script hangs up, Veeam Backup & Replication waits for 10 minutes and terminates the job.
  2. If you want to run several scripts that depend on each other, you must upload them to the VM guest OS manually. For example, you have script1.bat that sequentially starts script2.bat, script2.bat and script3.bat. In this case, you must specify a path to script1.bat in the job properties and upload script2.bat, script2.bat and script3.bat to the VM guest OS.

 

Transaction Log Truncation

If you back up or replicate virtualized database systems that use transaction logs, for example, Microsoft Exchange or Microsoft SQL Server, you can instruct Veeam Backup & Replication to truncate transaction logs so that logs do not overflow the storage space on the VM. Veeam Backup & Replication provides the following options of transaction logs handling:
  • Truncate logs
  • Do not truncate logs
  • Back up logs periodically
Transaction Log Truncation

Truncate Logs
You can instruct Veeam Backup & Replication to truncate logs after a backup or VM replica is successfully created. With this option selected, Veeam Backup & Replication behaves in the following way:
  • If the job completes successfully, Veeam Backup & Replication produces a backup file or VM replica and truncates transaction logs on the original VM. As a result, you have the backup file or replica that contains a VM image at a specific point in time.
In this scenario, you can recover a database to the point in time when the backup file or replica was created. As transaction logs on the VM are truncated, you cannot use them to get the restored database to some point in time between job sessions.
  • If the backup or replication job fails, Veeam Backup & Replication does not truncate transaction logs on the VM. In this scenario, you can restore a VM from the most recent backup or replica restore point and use database system tools to apply transaction logs and get the database system to the necessary point in time after the restore point.
Do not Truncate Logs
You can choose not to truncate transaction logs on the VM. This option is recommended if together with Veeam Backup & Replication you use another backup tool.

For example, you can use Veeam Backup & Replication to create a VM image backup and instruct the native Microsoft SQL Server log backup job to back up transaction logs. If you truncate transaction logs with Veeam Backup & Replication, the chain of transaction logs will be broken, and the Microsoft SQL Server log backup job will not be able to produce a consistent log backup.

With this option selected, Veeam Backup & Replication produces a backup file or VM replica and does not trigger transaction log truncation. As a result, you have a backup file or VM replica that contains a VM image captured at a specific point in time, and transaction logs on the VM. You can use transaction logs to restore the VM to any point in time between job sessions. To do this, you must recover the VM from the backup file or perform replica failover and use database system tools to apply transaction logs and get the database system to the necessary point in time.

Back Up Logs Periodically
This option can be used if you back up Microsoft SQL Server VMs and Oracle VMs.

You can choose to back up transaction logs with Veeam Backup & Replication. With this option selected, Veeam Backup & Replication creates a backup of a VM and additionally copies transaction logs and saves them to the backup repository next to the VM backup. After that, transaction logs on the VM are truncated.
In this scenario, you can use transaction logs to restore the VM to any point in time between backup job sessions. To do that, you must recover the VM from the backup file and use Veeam Explorer for Microsoft SQL Server or Veeam Explorer for Oracle to perform transaction log replay and get the database system to a necessary point in time.

 

Copy-Only Backup

Some organizations prefer to back up Microsoft SQL Server databases and transaction logs with native Microsoft SQL Server tools or 3rd party backup tools. To restore database systems in a proper way, database administrators must be sure that they have database backups and a sequence of transaction log backups associated with these backups at hand.

If you use native Microsoft SQL Server tools or 3rd party backup tools and also want to back up Microsoft SQL Server VMs with Veeam Backup & Replication, you must enable the Perform copy only option in the job settings.

The Perform copy only option indicates that a chain of database backups is created with native Microsoft SQL Server means or by a 3rd party tool, and instructs Veeam to preserve this chain (backup history). Veeam Backup & Replication backs up the Microsoft SQL Server VM using the VSS_BS_COPY method for snapshot creation. The VSS_BS_COPY method produces a copy-only backup — the backup that is independent of the existing chain of database backups. The copy-only backup does not influence the backup history — it does not change the last database modification date and time for the database (unlike non-copy only backups).


Copy-Only Backup Important!
Veeam Backup & Replication does not truncate transaction logs after copy-only backup. For this reason, if you instruct the backup job to perform copy-only backup, you cannot specify transaction log handing settings for this job.


Copy-Only Backup

Microsoft SQL Server Logs Backup and Restore

To protect Microsoft SQL Server VMs, you can instruct the backup job to create image-level VM backups and periodically back up database transaction logs. If Microsoft SQL Server fails, you can restore the Microsoft SQL Server VM from the necessary restore point of the image-level backup. After that, you can use Veeam Explorer for Microsoft SQL Server to apply transaction logs and get databases on the Microsoft SQL Server to the necessary state between backups.

Requirements for Transaction Log Backup
  • Veeam Backup & Replication supports transaction log backups for the following systems:
  • Microsoft SQL Server 2005
  • Microsoft SQL Server 2008
  • Microsoft SQL Server 2008 R2
  • Microsoft SQL Server 2012
  • Microsoft SQL Server 2014
  • The database whose logs you want to back up must use the Full or Bulk-logged recovery model. In this case, all changes of the Microsoft SQL Server state will be written to transaction logs, and you will be able to replay transaction logs to restore the Microsoft SQL Server. You can use the Microsoft SQL Server Management Studio to switch to one of these models. For more information, see http://msdn.microsoft.com/en-us/library/ms189275.aspx.

 

Transaction Log Backup Jobs

To back up transaction logs, you must create a backup job, add Enter value VM(s) to it and specify advanced settings for transaction logs backup in the job settings. The resulting job will comprise two jobs:
  • Parent backup job — the backup job that creates an image-level backup of the Enter value VM. The parent backup job is named , for example, Daily Job. You can configure the parent job in the Veeam Backup & Replication console just like any other backup job.
  • Child job — a transaction log backup job. To form a name of the child job, Veeam Backup & Replication adds a suffix to the name of the parent backup job: + Enter value Backup, for example, Daily Job Enter value Backup. Veeam Backup & Replication automatically creates the child job if it detects a backup job that is scheduled to back up at least one Enter value VM, and transaction log backup is enabled for this job. Session data of the transaction log backup job is stored in the configuration database and displayed in the Veeam Backup & Replication console.
The parent job runs in a regular manner — it starts by schedule or is started manually by the user. The transaction log backup job is triggered by the parent backup job. This sequence ensures that the VM (and the database) restore point is present when it comes to transaction log replay.

Sessions of Transaction Log Backup Jobs
The transaction log backup job runs permanently in the background, shipping transaction logs to the backup repository at a specific time interval (by default, every 15 minutes). A sequence of time intervals between sessions of the parent backup job makes up a session of the transaction log backup job.

The transaction log backup session starts and stops in the following way:
  • The initial session starts when the parent backup job schedule is enabled. After that, the session starts with every new session of the parent backup job.
  • The session ends before the next session of the parent backup job, and/or when this parent backup job is disabled.
  • When the session ends, Veeam Backup & Replication stops the runtime process and uninstalls it from the VM guest OS. When a new session starts, the runtime process is deployed again.

 

How Microsoft SQL Server Logs Backup Works

To perform transaction log backup, Veeam Backup & Replication installs the Veeam Guest SQL Log Shipper runtime component on the VM guest OS.

The component works during the transaction log backup job session. It collects information about databases that require transaction logs backup. It also detects whether it is possible to ship logs directly to the backup repository or Veeam Backup & Replication must use the log shipping server. When the transaction log backup job session ends, the component is stopped and removed from the VM guest OS. When a new session starts, the component is installed on the VM guest OS again.

The transaction logs backup is performed in the following way:
  1. Veeam Backup & Replication launches the parent backup job by schedule.
  2. The parent backup job creates an image-level backup of a Microsoft SQL Server VM and stores it on backup repository.
  3. A new session of the transaction log backup starts. Veeam Backup & Replication accesses the VM (directly or via the guest interaction proxy) and installs the runtime components for guest processing, database information collection and transaction log handing on the VM guest OS.
The runtime component copies transaction log files from the log archive destination (set by the Microsoft SQL Server administrator) to a temporary folder on the VM guest file system.
  1. Veeam Backup & Replication detects what databases currently exist on the Microsoft SQL Server and maps this data with the information kept in the configuration database. This periodic mapping reveals the databases for which Veeam Backup & Replication must process transaction logs during this time interval.
  2. Veeam Backup & Replication transports transaction log backup copies from the temporary folder on the Microsoft SQL Server VM to the backup repository, either directly or via the log shipping server, and saves them as VLB files. As soon as copies of transaction log backups are saved to the backup repository, transaction log backups in the temporary folder on the Microsoft SQL Server VM are removed.
The session of the transaction log backup job remains working until the next start of the parent backup job. When a new session of the parent job starts, the transaction log backup job stops the current session and then starts a new session, performing steps 1-5.

Transaction logs that for some reason were not processed during the log backup interval remain in the temporary folder and are processed during the next log backup interval. To detect these remaining logs, Veeam Backup & Replication enumerates log files in the temporary folder.

How Microsoft SQL Server Logs Backup Works Note:
If a new session of the transaction log backup starts and the parent backup job has not created a new restore point yet, the transaction log backup job will remain in the idle state, waiting for a new restore point to be created.

How Microsoft SQL Server Logs Backup Works

Retention for Transaction Log Backups

Transaction log backups are stored in files of the proprietary Veeam format — VBL. Veeam Backup & Replication keeps transaction log backups together with the VM image-level backup. The target location of VBL files depend on the type of the backup repository:
  • If you store the VM image-level backup on a simple backup repository, Veeam Backup & Replication writes transaction log backups to the same folder where files of the image-level backup reside.
  • If you store the VM image-level backup on a scale-out backup repository, Veeam Backup & Replication writes transaction log backups to the extent where the latest incremental backup file of the VM image-level backup is stored.
Veeam Backup & Replication removes transaction log backups by retention. You can choose one of the following retention methods:
  • Retain logs according to the image-level backup
  • Retain logs for the specified number of days
Retain Logs with Image-Level Backup
By default, Veeam Backup & Replication retains transaction log backups together with the corresponding image-level backup of the Microsoft SQL Server VM. When Veeam Backup & Replication removes a restore point of the image-level backup from the backup chain, it also removes a chain of transaction logs relating to this image-level backup. 

This method allows you to have both the image-level backup and necessary transaction log backups at hand. If you need to recover a database to some state, you can restore the Microsoft SQL Server VM from the necessary restore point and perform transaction log replay to bring the database to the desired state.

Retention for Transaction Log Backups

Retain Logs for a Number of Days
You can instruct Veeam Backup & Replication to keep transaction logs only for a specific period of time. This retention setting can be used, for example, if you want to save on storage space and plan to retain transaction log backups for the last few days. In this case, you will be able to restore the database only to one of the most recent states. 

If you select this retention method, you must make sure that retention policies for the image-level backup and transaction log backup are consistent. The restore point of the image-level backup must always be preserved. If a backup of the database itself is missing, you will not be able to perform transaction log replay.

Retention for Transaction Log Backups

 

Log Shipping Servers

For every Microsoft SQL Server VM whose transaction logs you want to back up, Veeam Backup & Replication defines how to ship logs to the backup repository. Transaction logs can be shipped in the following ways:
  • If it is possible to establish a direct connection between the VM guest OS and backup repository, log files will be shipped directly from the VM guest OS to the backup repository. This is the optimal method, as it does not involve additional resources and puts less load on the VM guest OS.
  • Otherwise, files will be shipped via log shipping server(s). You can instruct Veeam Backup & Replication to choose a log shipping server automatically from the list of available ones, or to use a specific server.
Note that if direct connection is possible, files will be always transferred from VM guest to repository directly (regardless of the configured log shipping server, as this server will not be involved). This approach helps to optimize performance at file transfer.

A log shipping server is a Microsoft Windows server added to the backup infrastructure. You can explicitly define what servers you want to use for log shipping or instruct Veeam Backup & Replication to automatically choose an optimal log shipping server. Veeam Backup & Replication chooses the log shipping server based on the location of the Microsoft SQL Server VMs and log shipping server.

Location of Log Shipping Server and VMs
When choosing a log shipping server for the job, Veeam Backup & Replication considers the location of the Microsoft SQL Server VM and log shipping server. Veeam Backup & Replication uses the following priority rules to select the log shipping server:
  1. Log shipping server is located on the source Microsoft Hyper-V host performing the role of the on-host backup proxy.
  2. Log shipping server and Microsoft SQL Server VM are located in the same network.
  3. Log shipping server and Microsoft SQL Server VM are located in different networks (the production infrastructure is isolated from the backup infrastructure).
That is, when choosing a log shipping server, Veeam Backup & Replication will give the top priority to a Microsoft Windows VM that is located on the source Microsoft Hyper-V host.

Log shipping servers are assigned per job session. When a new job session starts, Veeam Backup & Replication detects log shipping servers anew. Veeam Backup & Replication can also re-detect available servers during the job session. If a log shipping server becomes unavailable for some reason, Veeam Backup & Replication will fail over to another log shipping server.

Log Shipping Servers Important!
If you do not want to use some servers for transaction logs transport, you can manually define what server Veeam Backup & Replication must use as a log shipping server in the job settings. It is recommended that you assign the log shipping server role to a number of servers for availability purposes.


Log Shipping Servers

Transaction Log Backup Statistics

You can view the statistics of the transaction log backup job in the History view or in the Backup & Replication view in Veeam Backup & Replication.

In the statistics window, you can examine the overall statistics for the transaction log backup job, as well as view per-VM information. 

Transaction Log Backup Statistics

In the upper part of the statistics window, Veeam Backup & Replication displays information about the transaction log backup job for all VMs included in the parent backup job.

 

Support for AlwaysOn Availability Groups

AlwaysOn Availability Groups allow you to increase fault tolerance between active and hot-standby databases without involving shared physical disks, which is quite important for virtualization of Microsoft SQL Servers. Veeam Backup & Replication supports AlwaysOn Availability Groups for virtualized Microsoft SQL Server 2012 and later.

Image-level Backup of Microsoft SQL Server VMs
During image-level backup of a Microsoft SQL Server VM, Veeam Backup & Replication requests and analyzes information about databases that are included in the AlwaysOn Availability Groups. Depending on the retrieved information, Veeam Backup & Replication creates a VSS snapshot with or without COPY_ONLY flag. The VSS_BS_COPY flag for VSS snapshot is triggered if the VM represents a secondary node for at least one AlwaysOn Availability Group. 

Veeam Backup & Replication also detects to what cluster the database belongs. If the backup job does not include all VMs from the cluster, a warning message will be issued. 

Retrieved information is saved for further log identification.

Transaction Log Backup
Transaction log backup can be performed only for those databases that were successfully backed up, either on the primary or on the secondary node of AlwaysOn Availability Group. 

The transaction logs processing interval may be the same or may differ through VMs included in AlwaysOn Availability Group. If the interval is different, Veeam Backup & Replication will use minimal value (by default, 15 minutes). 

At each log processing interval, Veeam Backup & Replication chooses the AlwaysOn Availability Group node for which transaction logs will be backed up. 

Logs are backed up from one node of the AlwaysOn Availability Group. To become a subject for log backup, the node must meet the following criteria:
  • Required Veeam Backup & Replication components can be installed on this node (the VM must be running).
  • If there are any logs remaining in the temporary folder on the node of AlwaysOn Availability Group, this means these logs were not backed up to the backup repository during the previous session of the transaction log backup job, so this AlwaysOn Availability Group node must be processed first.
  • Databases in the AlwaysOn Availability Group(s) for this node were successfully backed up for the last two processing intervals.
  • Veeam Backup & Replication can establish a network connection to the node.
  • The VM is in the list of preferred nodes for backup retrieved from the Microsoft SQL Server. If there are no preferred nodes, any node can be chosen.

 

Oracle Logs Backup and Restore

Veeam Backup & Replication supports backup of Oracle database transaction logs and restore of Oracle databases. 

Database transaction logs are created by the Oracle system. The Oracle database can run in one of the following logging modes:
  • ARCHIVELOG turned on — logs are saved and can be used for recovery purposes.
  • ARCHIVELOG turned off — no transaction logs are saved. This mode is not recommended as it does not provide for proper disaster recovery.
With ARCHIVELOG turned on, the Oracle system stores database transaction logs to a certain location on the VM guest OS, as specified by the database administrator. Veeam Backup & Replication allows you to set up the following ways of log handling:
  • Instruct the backup job to collect log files from the Oracle VM and ship them to the backup repository where they are stored next to image-level backups of the Oracle VM.
  • Skip log processing — log files remain untouched on the Oracle VM and are preserved within the image-level backup.
If you enable application-aware processing for an Oracle VM, during the job session Veeam Backup & Replication installs a runtime process on this VM to collect information about the database and process transaction logs according to job settings. Application-specific settings are configured at the Guest Processing step of the backup job wizard — you can specify how logs should be backed up and\or truncated for Oracle databases. 

Requirements for Transaction Log Backup
  • Veeam Backup & Replication supports transaction logs backup and restore for Oracle database version 11 and later. The Oracle database may run on a Microsoft Windows VM or Linux VM.
  • Automatic Storage Management (ASM) is supported for Oracle 11 and later.
  • Oracle Express Databases are supported if running on Microsoft Windows machines only.
  • The database must run in the ARCHIVELOG mode.

 

Transaction Log Backup Jobs

To back up transaction logs, you must create a backup job, add Oracle VM(s) to it and specify advanced settings for transaction logs backup in the job settings. The resulting job will comprise two jobs:
  • Parent backup job — the backup job that creates an image-level backup of the Oracle VM. The parent backup job is named , for example, Daily Job. You can configure the parent job in the Veeam Backup & Replication console just like any other backup job.
  • Child job — a transaction log backup job. To form a name of the child job, Veeam Backup & Replication adds a suffix to the name of the parent backup job: + Oracle Backup, for example, Daily Job Oracle Backup. Veeam Backup & Replication automatically creates the child job if it detects a backup job that is scheduled to back up at least one Oracle VM, and transaction log backup is enabled for this job. Session data of the transaction log backup job is stored in the configuration database and displayed in the Veeam Backup & Replication console.
The parent job runs in a regular manner — it starts by schedule or is started manually by the user. The transaction log backup job is triggered by the parent backup job. This sequence ensures that the VM (and the database) restore point is present when it comes to transaction log replay. 

Sessions of Transaction Log Backup Jobs
The transaction log backup job runs permanently in the background, shipping transaction logs to the backup repository at a specific time interval (by default, every 15 minutes). A sequence of time intervals between sessions of the parent backup job makes up a session of the transaction log backup job.

The transaction log backup session starts and stops in the following way:
  • The initial session starts when the parent backup job schedule is enabled. After that, the session starts with every new session of the parent backup job.
  • The session ends before the next session of the parent backup job, and/or when this parent backup job is disabled.
  • When the session ends, Veeam Backup & Replication stops the runtime process and uninstalls it from the VM guest OS. When a new session starts, the runtime process is deployed again.

 

How Oracle Transaction Log Backup Works

The transaction logs backup for Oracle VMs is performed in the following way:
  1. Veeam Backup & Replication launches the parent backup job by schedule.
  2. The parent backup job creates an image-level backup of the Oracle VM and stores this backup to the backup repository.
  3. A new session of the transaction log backup starts. Veeam Backup & Replication accesses the VM guest OS to perform guest processing, collect database information and handle transaction log.
If Oracle runs on a Microsoft Windows server, Veeam Backup & Replication accesses the VM guest OS via a guest interaction proxy. You can instruct Veeam Backup & Replication to select the guest interaction proxy automatically or assign it explicitly. 

By default, Veeam Backup & Replication accesses the VM guest OS over the network:
  • For Linux VM guest OS — using SSH.
  • For Microsoft Windows VM guest OS — using RPC.
  1. Veeam Backup & Replication deploys the runtime process in the VM guest OS. The runtime process scans the Oracle system and collects information about databases whose logs must be processed, including:
  • List of all databases
  • Database state — a database is on or off, in which logging mode it runs
  • Paths to all database files (configuration logs and so on) and other data required for backup
Veeam Backup & Replication also detects whether it is possible to store logs to the backup repository through a direct access or a log shipping server is required. 

The runtime process copies transaction log files from the log archive destination (set by the Oracle administrator) to a temporary folder on the VM guest file system.
  1. Veeam Backup & Replication maps information about the Oracle system collected at step 4 with information kept in the configuration database. This periodic mapping helps reveal databases for which Veeam Backup & Replication must ship transaction logs to the backup repository during this time interval.
  1. Transaction log backup files are transferred from the temporary location on the Oracle VM to the backup repository, either directly or via the log shipping server. The source-side Veeam Data Mover compresses log data to be transferred according to its built-in settings. On the backup repository side, data is compressed according to the parent backup job settings.
If in the backup job settings you have specified that you want to delete archived transaction log backups from the VM guest OS, Veeam Backup & Replication will delete them from the temporary folder on the Oracle VM. 

Transaction logs that for some reason were not processed during the log backup interval remain in the temporary folder and are processed during the next log backup interval. To detect these remaining logs, Veeam Backup & Replication enumerates log files in the temporary folder.

How Oracle Transaction Log Backup Works Note:
If a new session of the transaction log backup starts and the parent backup job has not created a new restore point yet, the transaction log backup job will remain in the idle state, waiting for a new restore point to be created.

How Oracle Transaction Log Backup Works

 

Retention for Transaction Log Backup

Transaction log backups are stored in files of the proprietary Veeam format — VBL. 

Veeam Backup & Replication keeps transaction log backups together with the VM image-level backup. The target location of VBL files depend on the type of the backup repository:
  • If you store the VM image-level backup on a simple backup repository, Veeam Backup & Replication writes transaction log backups to the same folder where files of the image-level backup reside.
  • If you store the VM image-level backup on a scale-out backup repository, Veeam Backup & Replication writes transaction log backups to the extent where the latest incremental backup file of the VM image-level backup is stored.
Veeam Backup & Replication removes transaction log backups by retention. You can choose one of the following retention methods:
  • Retain logs according to the image-level backup
  • Retain logs for the specified number of days
Retain Logs with Image-Level Backup
By default, Veeam Backup & Replication retains transaction log backups together with the corresponding image-level backup of the Oracle VM. When Veeam Backup & Replication removes a restore point of the image-level backup from the backup chain, it also removes a chain of transaction logs relating to this image-level backup. 

This method allows you to have both the image-level backup and necessary transaction log backups at hand. If you need to recover a database to some state, you can restore the Oracle VM from the necessary restore point and perform transaction log replay to bring the database to the desired state.

Retention for Transaction Log Backup

Retain Logs for a Number of Days
You can instruct Veeam Backup & Replication to keep transaction logs only for a specific period of time. This retention setting can be used, for example, if you want to save on storage space and plan to retain transaction log backups for the last few days. In this case, you will be able to restore the database only to one of the most recent states. 

If you select this retention method, you must make sure that retention policies for the image-level backup and transaction log backup are consistent. The restore point of the image-level backup must always be preserved. If a backup of the database itself is missing, you will not be able to perform transaction log replay.

Retention for Transaction Log Backup

 

Log Shipping Servers

For every Oracle VM whose transaction logs you want to back up, Veeam Backup & Replication defines how to ship logs to the backup repository. Transaction logs can be transported in the following ways:
  • Directly from the VM guest OS to the backup repository. This method is recommended — it does not involve additional resources and puts less load on the VM guest OS.
  • Via log shipping servers. If it is not possible to establish a direct connection between the VM guest OS and backup repository, you can configure Veeam Backup & Replication to use a log shipping server.
A log shipping server is a Microsoft Windows or Linux server added to the backup infrastructure. You can explicitly defile what servers you want to use for log shipping or instruct Veeam Backup & Replication to automatically choose an optimal log shipping server. Veeam Backup & Replication chooses the log shipping server based on the location of the Oracle VMs and log shipping server.

Location of Log Shipping Server and VMs
When choosing a log shipping server for the job, Veeam Backup & Replication considers the location of the Oracle VM and log shipping server. Veeam Backup & Replication uses the following priority rules to select the log shipping server:
  1. Log shipping server is located on the source Microsoft Hyper-V host performing the role of the on-host backup proxy.
  2. Log shipping server and Oracle VM are located in the same network.
  3. Log shipping server and Oracle VM are located in different networks (the production infrastructure is isolated from the backup infrastructure).
That is, when choosing a log shipping server, Veeam Backup & Replication will give the top priority to a VM that is located on the source Microsoft Hyper-V host.

Log shipping servers are assigned per job session. When a new job session starts, Veeam Backup & Replication detects log shipping servers anew. Veeam Backup & Replication can also re-detect available servers during the job session. If a log shipping server becomes unavailable for some reason, Veeam Backup & Replication will fail over to another log shipping server.

Log Shipping Servers Important!
If you do not want to use some servers for transaction logs transport, you can manually define what server Veeam Backup & Replication must use as a log shipping server in the job settings. It is recommended that you assign the log shipping server role to a number of servers for availability purposes. 

Log Shipping Servers

 

VM Guest File System Indexing

You can instruct Veeam Backup & Replication to create an index of files and folders on the VM guest OS during backup. Guest file indexing allows you to search for VM guest OS files inside VM backups and perform 1-click restore in Veeam Backup Enterprise Manager.

VM guest OS file indexing is enabled at the job level. You can specify granular indexing settings for every VM in the job.

VM Guest File System Indexing Note:
VM guest file system indexing is optional. If you do not enable this option in the backup job settings, you will still be able to perform 1-click restore from the backup created with such backup job.

VM Guest File System Indexing

Requirements for VM Guest OS Indexing
  • Veeam Backup & Replication supports file indexing for VMs running Microsoft Windows and Linux OS.
  • Linux VMs must have the mlocate tool installed (a standard tool for majority of Linux distributions).

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