Help with mounting secondary VMFS datastore from snapshot

[Chemosh]

I am testing out the ability to recover particular VM's from a "replay"/snapshot on a Compellent SAN via iSCSI. The replay is just an earlier version, and I wanted to see if I can recover an earlier version of a test VM, but the GUI tools seem to be not setup to do so. My assumption is that the GUI tools see the mounted snapshot as having a similar ID to the already existing, original volume, and will not mount it; instead it wants to overwrite the information, which is counter to the entire point of the exercise. Is there a way to mount the snapshot, which presents itself as a new volume with it's own particular path and whatnot, and grab the files? I assume it will be a command line task, but I'm not overly familiar with the particulars of how VMFS3 works (I am beginning to move everything I can over to RDM however, as it seems to be more in line with my needs).

[Lightbulb · Accepted solution]

Checkout the following post

http://www.yellow-bricks.com/2008/12/11/enableresignature-andor-disallowsnapshotlun/

[JoJoGabor]

Have you set the LVM.DisallowSnapshot setting ont he host to 0 under advanced settings?

[titaniumlegs]

Don't use LVM.disallowsnapshot=0 when you have the original LUN attached. According to various sources at VMware, results are "unpredictable". You're basically telling ESX that the original LUN and the snapshot are the same thing. It's not guaranteed to corrupt, but there are scenarios where it can.

You should use LVM.EnableResignature=1, which will change the signature and mount it when the LUN S/N doesn't match the metadata.

[Chemosh]

After posting this, I had done more digging around and pieced together pretty much the same information in the blog entry. Thank you though for the quick responses!