Microsoft Clusters - the unsupported way?

[Grasshopper75]

Hi All,

I was wondering whether anyone is using MSCS virtual machines stored on SAN storage rather than local? I have used it this way in 2.5 with some minor issues but now VMware only support MSCS VMs on local storage. Although unsupported, is anyone still using Microsoft Clustered VMs stored on a SAN? I can't seem to see why it is still not possible?

The reason I ask this is because we are in the middle of migrating from 2.5 to 3.x and don't want to move away from the MSCS configs we have.

Basically I am trying to design a new fileserver which has its storage mapped to a SAN LUN. I need to consider recovery in the event of an OS outage and my current options are, MSCS Clusters, Snapshots or deploying a new VM and map to the same SAN LUN. I really do not want MSCS on local storage.

Any advice would be appreciated.

[stvkpln]

The reason VMware has the requirement for the boot volume for an MSCS cluster being on local disk because Microsoft has the requirement. There are some situations where you wouldn't necessarily want the boot volume of a clustered node to be on the SAN. In what situation, you may ask? Well, say your host has a path failure to the SAN and the vmkernel fails over.. if your clustered VM's have their boot volumes on the SAN, you're looking at potential cluster issues with the boot volume needing to failover, etc... It can lead to the cluster being in a rather odd state. That's the big reason behind this. Not using local storage on your hosts for the boot volumes (not the shared LUN/RDM) will put you in an unsupported configuration, both by VMware and Microsoft. Keep in mind, Microsoft does not support a similar configuration on physical servers, either (i.e. if you were doing boot from SAN for both physical boxes utilizing MSCS).

[kesparlat]

Hi,

MSCS is still supported in RDM. As I understand, you want MSCS to get High Avaiability on your fileserver, not for boot from SAN. If you do a 'cluster in a box' you won't get this avaiability.

Read the SAN compatibility guide. I remember that 4Gb HBA for MSCS is only supported above 3.0.2.

[Grasshopper75]

I guess MS clusters are definately out then as we don't have the local storage to store them.

So do I go with snapshots or redploy a VM and remap the LUN in the event of a disaster?

Due to constraints we currently don't currently use HA or perform full backups of VMs so I am looking for the best way to recover from a OS disaster for our fileserver.

I think the easiest way is to redeploy a new VM from a template and remap the LUN via RDM, recreate the file shares (which I will export from the registry) and away we go.

Not perfect by any means, but the company doesn't want to spend, so they get what they are willing to pay for!

[TomHowarth]

Remember it is only the boot disk that needs to be locally stored.

Tom Howarth

VMware Communities User Moderator