VMDK disk as Windows Cluster

[ubhatti1985]

Hi,

I have a quick question is it possible to use VMFS/NFS VMDK disks are windows clustering shared disks. I know you can have iSCSI shared disks on multiple hosts for windows clustering but want to know if we can do same with NFS or VMFS drives?

Regards
Umar

[MKguy]

Yes, you can build Windows Failover Clusters with shared VMDK disks sitting on normal VMFS volumes. Shared VMDKs on NFS however are not supported.

The caveat is that the shared VMDK on VMFS option is only formally supported for "Cluster-in-a-box" configurations where all VMs must reside on the same ESXi host.

This is probably not what you want for a clustered service where high availability is key. For "Cluster-acorss-boxes" with shared disks you have to use RDMs or in-guest ISCSI/SMB.

See these documents for more details:

Microsoft Clustering on VMware vSphere: Guidelines for supported configurations (1037959) | VMware K...

Microsoft Cluster Service (MSCS) support on ESXi/ESX (1004617) | VMware KB

http://pubs.vmware.com/vsphere-60/topic/com.vmware.ICbase/PDF/vsphere-esxi-vcenter-server-60-setup-m...

[ubhatti1985]

Hi MKguy,

Thanks for your reply.

I spouse we can use RDM without iSCSI in the guest OS?

Regards
Umar

[MKguy · Accepted solution]

Yes, RDM implies you use the host-side passthrough of a physical block storage device presented to the ESXi host as opposed to in-guest iSCSI, which is transparent to the host.

Both types support the cluster-across-boxes configuration.

[ubhatti1985]

Thank you very much.

[ubhatti1985]

Hi,

Another quick question when using RDM drives do you guys recommend to use new SCSI Controller i.e. if the VMDK (OS Drive) is running using SCSI Controller 0 should I use Controller 1 for RDM? So I can set the SCSI Bus Sharing to Physical?

Hope above make sense if not please let me know.

Regards
Umar

[MKguy]

Yes, when running clusters across hosts with RDMs you have to use an additional SCSI controller for the cluster disks and set its SCSI bus sharing mode to physical.

The detailed steps are explained in the MSCS guide starting from page 16 on the "Cluster Virtual Machines Across Physical Hosts" chapter and in the checklist on page 27:

http://pubs.vmware.com/vsphere-60/topic/com.vmware.ICbase/PDF/vsphere-esxi-vcenter-server-60-setup-m...