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6 Replies Last post: Apr 26, 2007 7:11 AM by jhanekom  

Guide to Creating a VMotion - able Microsoft Cluster with VI3 / ESX3 posted: Apr 19, 2007 1:50 AM

Click to view Gester's profile Novice 10 posts since
Feb 24, 2005
Hey Guys,

Well I've been using the forum for all the great info and even though I searched there wasn't a specific topic for exactly this, really only half hijacked threads that didn't actually explain what to do. So I thought I'd finally contribute something back :)

This is just a basic run down of what I did to finally get 2 VM's running Microsoft Cluster Services in VI3 with full VMotion support and ability.

1. Create your two VM's with Windows Enterprise and Cluster Services installed.

2. Ensure there are two NIC's to allow for the Heartbeat between the VM's. There should be a primary NIC and a private NIC that only has to talk to the other private NIC on the second VM.

3. Allocate on your SAN a raw LUN (4Gig) that is definately accessible by both ESX servers. On the first VM you should have your boot volume on one SCSI device and any other drives needed on the first SCSI controller.

4. Add a new disk to the VM then select RAW Mapping. Select the Host SCSI ID that correlates to your raw LUN that you created and select next. Make sure you place the new disk onto a spare SCSI channel. In my case 1:0. I guess it should be standalone. This will automatically create another LSI SCSI Adapter in your hardware config.

Now the confusing part: Put the disk into Virtual Mode, then select the disk to be Independant AND Non-Persistant. This was the part that stumped me for ages.

5. Power on the first VM with the new RDM disk created. You must make sure that there is NO bus sharing on the new SCSI Adapter. It should default to None anyways.

6. Log into Windows and format the new drive that it detects and assign it a drive letter, eg "Q:".

7. Shutdown the first VM and select to edit the second VM settings. Go through the same process as step 4 and make sure that the SCSI Channel is also set to 1:0 (or whatever it is in the first VM). Also make sure its Independant and Non-Persistant.

8. Power on both servers and providing your networking is setup correctly start creating a new MCS and it lock in the new Quorum disk automatically and be successfull!

Now I know this is a real brief description and yes probaly some steps could be changed / done differently but this is just what I had to do to get it going :) I was pulling my hair out! What I tried is just a combination of what I've found on the forums but it was still hard to find and I saw alot of new people weren't quite understanding what was being told. In the end the process really is quite simple.

I'm definately not a guru but it might actually help someone :)

Any questions please feel free to ask!
Click to view Gabrie's profile Master 887 posts since
Jun 6, 2005
I always was under the impression that it is NOT supported to put the vmdk of your C-drive of your Windows cluster on SAN because of possible timing issues. And therefore you could not vmotion a cluster node.

So, yes you will get it working and even do a VMotion, but the risk of spontanious cluster failovers because of timing issues, will give you troubles in a production environment.

Gabrie
Click to view conyards's profile Expert 473 posts since
Sep 22, 2006
Another way of achieving a Vmotionable, HA enabled, functioning but quite unsupportable in production MSCS cluster would be to use majority node sets for the Quorum volumes.

Simon
Click to view jhanekom's profile Master 1,084 posts since
May 13, 2005
The document you mention is quite clear that your boot disks MUST live on local storage. http://www.vmware.com/pdf/vi3_301_201_mscs.pdf, page 17. So VMotioning an MSCS node is a definite no-no in terms of support.

Personally, the MSCS requirements have been in such a state of flux and so many people have been burnt by systems suddenly becoming "unsupported", that I recommend to my clients that they stay away from implementing MSCS on VMware.

In stead, I try to convince them that HA is good enough or, failing that, to implement MSCS on physical machines. In most cases, the cost benefits win out, and they just go with HA.
Click to view jhanekom's profile Master 1,084 posts since
May 13, 2005
Hi Gester

I don't think we're reading the same document. Can you point me to the one you're reading?

The one I linked to above makes no mention of having system disks on shared storage other than to expressly forbid it. The only registry keys in it are the standard "Set disk TimeOutValue to 60", which VMTools generally does for you anyway and doesn't have that much to do with clustering.

Regarding Majority Node Set: the clustering document specifically states you may only use two-node clustering (page 49.) With my limited understanding of MNS clustering, that rules it out as a possibility. (Minimum number of servers required for quorum is 3?)

As Gabrie has mentioned, it may work now, but you may get erratic behaviour at times and you will be on your own in terms of production support.

Message was edited by:
jhanekom
(added info on MNS)

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