Q: How do I configure the drain on shutdown feature on myR2 Hyper-V failover cluster?
A: Typically, if you place a node in maintenance mode in Windows Server 2012, all virtual machines (VMs) are live migrated to another node—resulting in no loss of availability of VMs. However, if you don't place a node in maintenance mode and you simply shut down the node instead, the VMs' states are saved to disk, moved, and then resumed. This makes them unavailable for a period of time.
Windows Server 2012 R2 remedies this problem with the drain on shutdown feature, which performs a live migration of VMs during shutdown even if the node wasn't placed in maintenance mode. (You should still place nodes in maintenance mode whenever possible.) The drain on shutdown feature is enabled by default. To verify this setting, view the DrainOnShutdown cluster property (1 means enabled; 0 means disabled):
PS C:\> (Get-Cluster).DrainOnShutdown