Configuration (Virtual Machine)

Creating MSCS Machines

There are various different configuration options for creating MS clusters. For production standard clusters you must use RDM, otherwise you're forced to host both your VM's on the same ESX (and you can't vMotion them!).

• You can't snapshot disks that are configured to use SCSI Bus Sharing.

Disk Type	SCSI Bus Sharing	Cluster in a Box 2 VM's / 1 fixed ESX	Cluster Across Boxes 2 VM's / multi ESX	Virtual/Physical Hybrid 1 VM + 1 Physical
Normal VMDK	Virtual	Yes	No	No
RDM	Virtual	Yes	Yes - Win2k3 only	No
RDM	Physical	No	Yes	Yes

• Window 2003 servers must use LSI Logic Parallel SCSI controller for shared disks
• Window 2008 servers must use LSI Logic SAS SCSI controller for shared disks

See the following for further info

• VMware KB 1004617 - Microsoft Cluster Service (MSCS) support on ESX - Links to PDF docs for each flavour of ESX
• VMware KB 1037959 - Microsoft Clustering on VMware vSphere: Guidelines for Supported Configurations - Supported infrastructure config matrices

Cluster in a Box

Procedure assumes you're creating a VM cluster using 2 VM's on the same server sharing standard VMDK disks (not RDM's)

1. Create a new private vSwitch on the ESX to host the VM's called "MSCS Heartbeat"
2. Create two VM's...
   • Don't create the shared disks yet
   1. With 2 NIC's, 1st attached to normal (externally accessible) network, 2nd attached to private "MSCS Heartbeat" network
   2. Boot up and ensure they're working as expected (not as a cluster yet), then shutdown
3. On the 1st VM...
   1. Create the required shared disks on a new SCSI Bus ID
      • Tick Support clustering features such as Fault Tolerance, which ensures the disks are created in eagerzeroedthick format
      • Select a new SCSI Bus ID in the Virtual Device Node drop-down box, which creates the disks on a new SCSI Controller
   2. Change the new SCSI Controller's config...
      • SCSI Controller Type should be set to LSI Logic SAS (Win2k8) or LSI Logic Parallel (Win2k3)
      • SCSI Bus Sharing should be set to Virtual
4. On the 2nd VM...
   1. Create the required shared disks on a new SCSI Bus ID, selecting Use an existing virtual disk (you'll need to locate the shared disks already created)
   2. Change the SCSI Bus Sharing mode of the new SCSI Controller to Virtual
5. Boot the VM's up, disks should be visible from Disk Management from both VM's
   • Only format from one machine, NTFS doesn't support access from more than one host, MSCS needs to manage volume access/ownership