EMC Replication Manager With vSphere 4 and LVM.EnableResignature

Posted: September 26, 2009 in Celerra, Replication Manager, VMware

Ive had Replication Manager 5.2 integrated with VMware VI3, hanging off an EMC Celerra using iSCSI for some time now, and ever since vSphere was released Ive been meaning to test the functionality to make sure everything works and to see if there are any changes.

Now having set this up with 3.5 update 4 hosts I remembered one of the key steps is changing the advanced LVM.EnableResignature option to 1 which allows a snapshot of an existing lun with a matching header to  automatically re signature and be presented back to the host. If you want to read more about how this works then Chad Sakac has a really good post about this here.

 Here is a screenshot showing this on a ESX 3.5 host.



The next step was to build my self a vSphere 4 host and integrate it into my existing lab setup, after building the host and searching through the advanced options I realised the LVM.EnableResignature option was not available and after a quick google it didnt take long to find this post by Duncan at Yellow-Bricks.

After configuring the host in Replication Manager I performed a Mount of an existing snapshot to my vSphere1 host, the task completed successfully but I was unable to see the lun on the host.

The image below shows the snapshot has been succesfully mounted to the host.


You can see only the default datastore on local disk and the original Celerra Lun is shown.





Next I went to Configuration >> Storage >> Add Storage >> Disk/Lun and there it was.


 After selecting the lun and clicking next, I was now presented with three options as shown in the screenshot below.



As Duncan pointed out in his post, yes this can be done through the GUI but its more fun from the command line, im also a firm believer of learning to do tasks from both the command line and the GUI.

So with that said im now going to use vicfg-volume to resignature the lun.

First lets check the existing header ID  using vicfg-volume.pl – -server vsphere1 -l


Now lets resignature the lun using vicfg-volume.pl – -server -r <existing_header>


Next I check to see if the lun is now visible, and there it is.






Just as a last note to this post I just wanted to mention Ive not yet found anything in the release notes to confirm vSphere is supported with Replication Manager 5.2.2, so at the moment this is nothing more than an informational post. Ill make sure to update this as soon as Ive confirmed this is in fact supported.

Oh and just incase you’re wondering why this change has come about…. With VI3 and LVM.EnableResignature it was an all or nothing setting, now with vSphere 4 you can change this on a per Lun basis, actually a good thing once you know about it.

If you’re a VMware shop you have to check out some of the demos online, Replication Manager is a Brilliant product !


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