How to add a replicated LUN to vCenter for disaster recovery testing?

[pegasus20111014]

We are currently on version 5.1 of vCenter and ESXi.  We have a DR test coming up for one of our applications which includes approx 12 VMs.  My question is, when presenting the replicated LUNs to our DR / Test vSphere environment at our DR site, should we choose to resignature the LUNs?  I thought I had read somewhere that in order for all hosts in a VMware cluster to see the LUN, it needs to be resignatured, as opposed to just mounting the LUN without resignaturing, which I believe can only be presented to one host when doing it this way.  I just wanted to confirm whether or not this is correct.

Also, if resignaturing the LUN, will we need to manually update references for each VMs vmdk files, or is that done automatically?

When doing a DR test previously and just choosing to mount the LUN and not to resignature, the LUN was only visible on that one host which is in a three node cluster.

Thanks

[a_p_ · Accepted solution]

What's going to happen when you present a LUN to a host depends on whether the host has seen the signature before, i.e. the LUN was mounted previously and has not been unmounted/detached properly. In case of a known signature, the LUN will be treated as a "Snapshot LUN" and you either have to resignature it to make it appear as a new LUN to the host, or you need to manually force mount the LUN. With resignaturing the LUN from one of the hosts, it will be recognized by all of the other hosts too. Force mounting has to be done on each of the hosts separately. For details see http://kb.vmware.com/kb/1011387.

You may also want to take a look at http://kb.vmware.com/kb/2004605 for how to properly unmount/detach a LUN from a host, so that it should not remember the signature anymore.

André