If you are configuring a cluster with less than 2 datastores, you will receive an HA warning “The number of heartbeat datastores for host is 1, which is less than required: 2” You can add an option to the HA Advanced Options to supress this warning.

1. Log in to vCenter Server
2. Right-click the cluster and click Edit Settings
3. Click vSphere HA > Advanced Options
4. Under Option, add an entry for das.ignoreInsufficientHbDatastore
5. Under Value, type true
6. Click Cluster Features
7. De-select Turn on vSphere HA and click OK
8. Wait for all the hosts in the cluster to re-configure HA, then …

This is a great script to keep handy. If you have multiple RDM’s on a VM and need to get the NAA_ID for them the below PowerCLI command will get you that information.

1Get-VM VMNAME| Get-HardDisk -DiskType "RawPhysical","RawVirtual" | Select Parent,Name,DiskType,ScsiCanonicalName,DeviceName,CapacityGB | fl

If you then need to match the SCSI virtual disk to the Guest OS this is a great article on how to do so.

KB2051606