Users Guide

Administering High Availability for Hyper-V 47

Ownership of HA resources can be verified using the Failover Cluster

console. Check the Resource Groups listed under Services and Applications

to verify ownership of HA VMs and check the Storage section to verify

ownership of disk resources. If the physical disk resource listed under

Available Storage and the virtual machine resource are owned by separate

nodes, either of the resources needs to be moved so that they are both on the

same node. If migrating the VM to the other node is not a viable option, then

the storage resource may be moved. The latter is achieved via CLI. For

example, the CLI command cluster group "Available Storage"

/move can be used to move storage disks across nodes in a two-node cluster.

Once the resources are owned by the same node, make sure the HA VM is in

Off or Shutdown state and then proceed with adding the passthrough disk to

the VM by updating the VM's hardware configuration.

NOTE: In order to enable the above functionality, Hyper-V allows passthrough

disks that are already Available Storage cluster resources to be added an HA VM.

However, currently Hyper-V does not check if a passthrough disk is already an

allocated cluster resource before allowing it be added to an HA VM. However,

currently Hyper-V does not explicitly check if a passthrough disk is an Available

Storage cluster resource or whether it is an allocated cluster resource before

allowing it be added to an HA VM. Make sure that the correct passthrough disk is

being attached.

Sharing LUNs Between HA VMs

With the 951308 QFE applied, Windows Failover Cluster allows multiple HA

VMs to be hosted within the same Resource Group. This is a critical

requirement for scenarios such as when multiple HA VMs have VHD files on

the same storage LUN. However, careful consideration needs to be given

before multiple HA VMs are hosted within a single resource group because

the resource groups failover as a single entity. All of the VMs hosted on a

single resource group will failover simultaneously.

Multiple VMs can share a storage LUN only if the VMs are using VHD based

rather than passthrough disks. Use the following guidelines to add a new VM

to an existing HA VM group:

If a Resource Group has not been created already, use the procedures from

"Implementing High Availability in Hyper-V" on page 35 to create an HA

VM, for example

HA-VM1