Comments on: Gotcha Adding Disk to Virtual Oracle RAC Cluster with VMware multi-writer flag

By: New method of enabling Multiwriter VMDK flag in vSphere 6.0 Update 1 (UI + API) | virtuallyGhetto

Mon, 19 Oct 2015 14:50:18 +0000

[…] For those interested in Automating the Multiwriter VMDK flag, I have created a quick PowerCLI sample called configureMultiwriterVMDK.ps1 which demonstrates this new vSphere API. You will need to specify the name of the VM as well as the label of the VMDK in which you wish to enable the Multiwriter VMDK flag (e.g. Hard disk 2). Below is an example of running the script. If you wish to add a new VMDK and enable the Multiwriter flag all at once, you can reference my script and using the following PowerCLI sample provided by Michael Webster here. […]

By: David

David — Wed, 12 Aug 2015 04:38:29 +0000

Thanks for the script Michael. BTW I was having an issue while running the first script with both vSphere 5.5 and 5.1 so thought of sharing my “quick fix” in case someone faces the same problem. I had to change the following line in order to get it working:

[int64]$capcitykb = ($capacity * 1gb) / 1kb

into this

[int64]$capcitykb = $capacity * 1048576

Not sure why but that did the trick for me.

Cheers.

By: vcdxnz001

vcdxnz001 — Wed, 08 Oct 2014 15:33:11 +0000

In reply to Davros. Hi Davros, You could also use the Perl SDK or one of the other VMware SDK\'s to achieve the same thing, but the PowerShell CommandLets are very powerful once you figure out how to use them. I\'ve also checked and this still doesn\'t work in vSphere 5.5 Update 2, even though the problem was meant to be fixed.

By: Davros

Davros — Tue, 07 Oct 2014 15:42:33 +0000

Hi, I really wish I could find the above simple. Unfortunatley I don't (I really struggle with PowerShell in comparison to BASH).

Is there a simpler way than above? Say I already had the disks created, setup as independent etc. All I actually need to do is set the values:

scsi1:0.sharing = multi-writer
scsi1:1.sharing = multi-writer

for a VM named env-test

Can anyone help?

By: Lenny

Lenny — Wed, 17 Sep 2014 14:00:25 +0000

In reply to vcdxnz001.

FYI — http://houseofbrick.com/esxi-5-5-multi-writer-bug/

That post is based off of the work they did for us on a PoC I am leading for Oracle RAC VMs.

By: vcdxnz001

vcdxnz001 — Mon, 15 Sep 2014 19:54:52 +0000

In reply to Lenny. Hi Lenny, I haven't installed Update 2 for ESXi 5.5 yet, but that is my understanding. This was a bug and has now been fixed. Next bug I'm trying to track down is running more than 26 ASM disks in one VM.

By: Lenny

Lenny — Mon, 15 Sep 2014 19:52:51 +0000

Can confirm … ESXi 5.5 Patch 2 Build 1892794 brought back this functionality. VMSupport confirmed to me that its absence was indeed a bug.

By: Martin

Martin — Mon, 15 Sep 2014 09:12:59 +0000

In reply to vcdxnz001. It looks like it's fixed in vSphere 5.5U2

By: vcdxnz001

vcdxnz001 — Mon, 08 Sep 2014 11:13:32 +0000

In reply to mike. Hi Mike, Yes you are correct. You can't really take a snapshot of the VM's using VMware based snapshots. However you can take storage based snapshots, or you can use RMAN. The preferred method is still to use Oracle RMAN integrated technologies. VMware doesn't yet recognise multi-writer disks or clusters with regard to their snapshot technology or other technologies including provisioning operations, storage vMotion etc.

By: mike

mike — Mon, 08 Sep 2014 08:54:58 +0000

Do you have any experience backing up oracle RAC VM? I believe VMware has a limitation to run a snapshot in a share disk with multi-driver enable.