SRM and RDM with different LUNs at the protected site and recovery site

[WarlockArg]

Hi,

   I have a question whether the following scenario is supported or not. I have a VM with two virtual disks. One is a normal vmdk and the other one a RDM (virtual or physical). The vmdk is located on a datastore that is the only one in a LUN that is being replicated to the recovery site via array replication. The RDM map file is also located on the same datastore as the vmdk is, and the RDM LUN (the LUN with the actual data) is a LUN that of course is presented to the ESXi where the VMs runs on (let's suppose the LUN ID is 10). That LUN (10) is replicated to the recovery site but on that site the LUN ID is another one than 10, for example LUN ID 20.

     May I protect the VM with SRM? If the answer is "yes", how does the VM at the recovery site when the recovery plan runs know that the new data LUN is now the LUN ID 20 and not the LUN ID 10 that had been set up in the protected site? Because the vmx file and the RDM map file that is in the replicated datastore are pointing to the same LUN ID that pointed in the protected site. Or it doesn't?

     If the answer is "no" I have two workarounds for this issue. The first one is to replicate the RDM Data LUN with the same LUN ID in the protected site and the recovery site. The second one is having a script (or PowerCLI script) that should be run before the VMs at the recovery site begin to startup. The script would change the VM's configuration in order to point the RDM to the correct LUN ID (in this case, LUN ID 20). This second workaround would be possible as long as SRM permits to protect this VM, because I suppose it will know, via its SRA, that the replicated LUN ID at the recovery site is not the same as the LUN ID at the protected site. Perhaps, because it knows that difference SRM doesn't protect the VM at all. I really don't know its behavior in this kind of scenario.

     Anyway, in the last case the question is, do I have any way to run this script automatically at some point in the recovery plan?

Thanks,

[bayupw · Accepted solution]

Hi

Most of the time I see the LUN ID will be differ between protected and recovery site, so I don't think it would be a problem.

What storage are you using?

You can review the storage documentation check if the doc saying anything particular about LUN ID requirements.

I have listed some of the storage documentation related to SRM here: SRM Deployment Guide Documentations from Storage Vendor

It is better to put the vmdk and RDM in the same controller as most of the storage does not support storage replication layout from different array with RDM.

VMware KB related with this: VMware KB: Protection and recovery of virtual machines when LUN replication is from one or more arra...

Here's an example for NetApp storage taken from this doc http://www.netapp.com/us/system/pdf-reader.aspx?m=tr-4064.pdf&cc=us

A single virtual machine cannot own data (vmdk or RDM) on more than one SRM array (physical NetApp controller or MultiStore® vFiler unit.)

To be able to protect a VM with SRM and the NetApp SRA, all parts of the VM must exist on only one NetApp controller or MultiStore vFiler unit, in both the protected and recovery site.

Do you have SRM installed/implemented in your environment?
If you have the storage snapshot license, you can perform an SRM Test first to see if it works.