Node Fairness is a latest feature of Failover Clustering (not Hyper-V) that will automatically Live Migrate guests VMs away from an overloaded cluster node. Even though it is a Failover Clustering feature, it only operates on Hyper-V virtual machines.
In this article, we'll show you how Node Fairness works in hyper-v 2016 and how to set it up.
How Does Node Fairness Work?
When triggered, the cluster service will check the host for the presence of two conditions:
- Has the physical host’s average CPU load (not what you see in Task Manager) exceeded the tolerance threshold in the past five minutes?
- Is the physical host’s current memory load above the tolerance threshold?
If either of the conditions are true, the host is a candidate for re-balancing. The heuristics for how it chooses which virtual machines to migrate is not published, and I was not able to determine any distinguishable pattern through my own testing. We may discover more in future.
How is Node Fairness Triggered?
- Every 30 minutes (the default)
- When a node joins the cluster. Applies either from a new node joining or an existing node rejoining, such as after a reboot.
What About Storage, Networking, and Power Loads?
How Does Node Fairness Interact with Virtual Machine Manager’s Dynamic Optimization Feature?
How to Configure Node Fairness?
Enabling, Disabling, or Changing Hyper-V Node Fairness’s Operating Mode with PowerShell$Cluster = Get-Cluster clhv01
$Cluster.AutoBalancerMode = 0
Setting Hyper-V Node Fairness’s Balancing Mode with PowerShell$Cluster = Get-Cluster clhv01
$Cluster.AutoLevelerMode = 1
How to set up Hyper-V Node Fairness in Failover Cluster ManagerIn Failover Cluster Manager (Windows 10/Windows Server 2016 or later only), right-click on the cluster object in the left pane and click Properties.
In the properties window, switch to the Balancer tab.
Modify the options in accordance with your desires.