Create Shared Disks for Oracle RAC Clusters in VMware

C# Client doesn’t have specific features like choose multi writer flag . So better do to do it using Web Client.

The multi-writer option allows VMFS-backed disks to be shared by multiple virtual machines. Used by Third-party cluster-aware applications like RedHat 6 or later with GFS File systems and Oracle RAC Clusters.

If the SCSI Controller is not added, Machine needs to be offline in order to do it.

Lets see how to do it.

Edit Settings of the First Node in the Cluster.

Add SCSI Controller Add

In SCSI Bus Sharing : None

Change Type : Vmware ParaVirtual

Now Add the Hard Disk in the First node in the Cluster

Now Choose

• Thick Provision Eager Zeroed
• Sharing Multi Writer
• Choose Virtual Device Node you just created.
• In my Case SCSI Controller 1 – SCSI 1:0
• Disk mode – Independent Persistent

Now All done with the First Node. if you need more Shared Disks on the Same Virtual Machine. You can use the Same Physical Controller you Created

Additional Disk2 will be SCSI 1:1

Additional Disk3 will be SCSI 1:2

Now Edit Settings Copy the Disk File Name you just Created. For Example – [DataStore1]Vmname/Vmname_1.vmdk

Note : From Third Disks onwards You have to Choose Manage other disks in order to change its settings.

Now go to Second Node in the Cluster –

Add SCSI Controller Add

In SCSI Bus Sharing : None

Change Type : Vmware ParaVirtual

Now Add Existing Disk –

Now Choose

• Thick Provision Eager Zeroed
• Sharing Multi Writer
• Choose Virtual Device Node you just created.
• In my Case SCSI Controller 1 – SCSI 1:0 Matching the First Node to be precise.
• Disk mode – Independent Persistent

Disadvantage of doing this Now Storage Vmotion is not Possible.

Good to know –

If its a Red HAT VM . Below ensures that the disks falling out of order will not cause issues in ASM

1. shut down your virtual machine
2. right-click on the VM’s entry in the left-hand panel and select Edit Settings
3. click on the Options tab
4. select the Advanced -> General item on the left and click on the Configuration Parameters
5. Click on the Add Row button
6. Click Add Row.
7. In the Name column, enter disk.EnableUUID
8. In the Value column, enter TRUE
9. Click OK and click Save.
10. Power on the virtual machine.

Reference –

https://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1034165

https://access.redhat.com/solutions/94583

https://access.redhat.com/solutions/158873