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mjcb
Contributor
Contributor

ESX 4 Update 1 and Microsoft Clustering

Hello,

I was wondering if anyone could clarify things for me. We were looking at virtualizing our file clusters this year but after reviewing the limitations I see that i cannot. So here are my questions:

  1. Does not support NPIV. Why would that be..anyone know the technical reason behind that. we use HP C-Class Blades for our ESX environment, so NPIV is mandatory. If the Microsoft Clustering supports it I am confused why ESX wouldn't. (we would use raw device mapping of a LUN)

  2. Doesn't support VMotion of a clustered VM. This is strange to me since Update 1 enabled support for HA and DRS.

While doing a google on NPIV and Clusters in ESX, I ran into something that also stated that you cannot have more than a 2 node cluster. Is this true? That would also be a killer for us.

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VMmatty
Virtuoso
Virtuoso

Before you do anything else I would read this document:

http://www.vmware.com/pdf/vsphere4/r40/vsp_40_mscs.pdf

Specifically, check out page 13 where they list the limitations of MSCS clustering on vSphere.

It states that clusters are not supported in a DRS/HA cluster. In order to maintain compliance you need to exclude those VMs from participating in DRS or HA. And you can't VMotion those VMs as well, though I dont think there is a way to prevent someone from doing it manually. Using VMotion on a clustered VM has been known to cause problems. I've seen it myself - since Microsoft clusters are very particular about lost network connectivity, the loss of the single ping during VMotion can often cause a cluster failover. I saw that happen as recently as last week with vSphere 4 Update 2.

Virtualizing MS clusters doesn't work in all situations. I would recommend reading the document and making sure that you fit the requirements to have a supported configuration. If not then I would keep the clusters physical. I wish that VMware (and Microsoft) would make it a little easier to virtualize clusters but unfortunately we're just not there yet.

Matt | http://www.thelowercasew.com | @mattliebowitz
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AureusStone
Expert
Expert

I think VMmatty answered everything.

But I will mention that it isn't that vSphere can not handle more then two nodes. Actually it does work, it is just not supported, so I recommended you don't do it.

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mjcb
Contributor
Contributor

Thanks guys,

If you take a look at the update 1 documentation you will see that MSCS now support HA and DRS. (limited) Update 1 included some advanced clustering enhancements. That is why I am a little confused on why VMOtion is not supported. The funny thing is that it supports DRS however you have to disable the automation around it.....so really not sure how DRS itself is supported. Also looking at it more, it still only supports 2 node clusters, so I guess I am staying physical..for now.

I've attached the updated documents below.

Update 1 release notes:

http://www.vmware.com/support/vsphere4/doc/vsp_esx40_u1_rel_notes.html

Updated Clustering Guide

http://www.vmware.com/pdf/vsphere4/r40_u1/vsp_40_u1_mscs.pdf

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RParker
Immortal
Immortal

Does not support NPIV. Why would that be..anyone know the technical reason behind that. we use HP C-Class Blades for our ESX environment, so NPIV is mandatory. If the Microsoft Clustering supports it I am confused why ESX wouldn't. (we would use raw device mapping of a LUN)

Where does it say that? WE have had ESX since 3.02, and every one (as far as I can remember) supports NPIV.

Doesn't support VMotion of a clustered VM

How can you migrate a clustered VM? If they are tied to the same VM, ESX has no way of knowing that the VM can be moved, since it's configured for the same disk. Clustering is local storage usually, so they can't be vMotion since the shared storage is local to the host, not between hosts.

I ran into something that also stated that you cannot have more than a 2 node cluster. Is this true? That would also be a killer for us.

You left out the words "On the SAME host . . . . . . .". This is why they have a consolidation test, to check your machines BEFORE you virtualize to see if they are good candidates.

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mjcb
Contributor
Contributor

  1. Page 13 under the limitations of the clustering it states that NPIV is not supported. When I mentioned this I meant the MSCS under ESX is not supported, not ESX itself.

  2. My thinking is that since the Microsoft Clustering Service manages the disk ownership not ESX, so it should be able to work. Reading through the clustering guide it does show that 2 nodes can reside on different hosts. (Page 21 of the clustering guide). Page 9 also shows that "A shared disk is required as a quorum disk. In a cluster of virtual machines across physical hosts, the shared disk must be on a Fibre Channel (FC) SAN".

  3. Looking at page 12 of the guide, it shows that number of nodes that are supported are 2 for all vSphere MSCS configs, so not sure if i am missing something.

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