Forced to format LUN?

[Borat_Sagdiev]

I'm having a problem adding a LUN to one of my ESX hosts, just wondering if this is by design or if I am doing something incorrectly.

I replicated a LUN using NetApp SnapMirror from Host 1 (Source) to Host 2 (Destination). In order to facilitate this I had to disconnect the original LUN from host 2 while it was being overwritten with the new data. Problem: when it was time to reconnect, I rescanned my storage adapters, rescanned for VMFS volumes and proceeded to add the LUN back. Now I can not add the LUN without being forced to reformat it. In other situations when I've added a fresh LUNs to a host in a cluster, the first host that it connects to usually asks to format while the second hsot in a cluster does not, I suppose it's aware of the fact that it is already formatted.

Is this normal or did I miss a step?

[Dave_Mishchenko]

Try to rescan your storage with the LVM.EnableResignature option set to 1.

For more info on it, take a look at the updates section in the below PDF - pages 4/5.

http://www.vmware.com/pdf/vi3_301_201_san_cfg.pdf

[Borat_Sagdiev]

Dave,

I tried that, but no changes. Virtual Center just queues the job and errors out after a few minutes. I did notice that after I rescanned my storage adapters with the LVM change, the LUN is now called snap-00002lun1 instead of the original name which let's say would be "lun1".

Any thoughts?

[sbeaver]

Something is wrong with you pathing and esx sees the paths to the sam LUN as 2 different LUNS. You need to allow for snapshots to see that LUN and then you should move everything off and destroy / recreate the LUN again

[Eddy]

Conf. Advanced Settings, LVM, LVM.DisallowSnapShotLun is what may be causing your grief..

I have had the need to present a SNAP back to an ESX server in an emergency and when I modified the above trigger, I was able to see and attached to my lun..

In the LAB I have played with a LUN presented to an ESX Server via Fiber, I then Snapped it and presented it back to the same ESX via iSCSI and it worked as well...

One other option you may want to try if you cant get this to work is to make a new LUN from the Snap.. Basically a SnapCopy