Recovering VM at second DC if entire production DC is down.

[jhardwood]

We have two Data Centers (DC1 and DC2).  We are replicating VMs from DC1 to DC2 with a vSPhere appliance running in DC1.  If the entire DC1 goes down (including the appliance) will we be able to recover the VMs that have been replicating at DC2?  Or does the fact that the replication appliance is also down (because DC1 is completely down) make the vSphere Replication unavailable in the Web Client at DC2?  If the later, how do we handle a complete DC1 failure and get those replicated VMs up and running at DC2?

Thanks kindly,

Jeff

[weinstein5]

You should be able to recover if DC1 is down - this might provide come additional information - http://www.vmware.com/files/pdf/techpaper/Introduction-to-vSphere-Replication.pdf

[jhardwood]

Thanks for the prompt reply and the link to the pdf.  After reading, I am still not sure of how I will get to the "Vsphere Replication" and "Recover" functions in the web client if my entire production data center is down, which includes the replication appliance that normally provides these functions.  How does my VCenter server on the DR side know about these replicating VMs without the appliance?

jeff

[mvalkanov]

Hi,

If this is replication within a single vCenter Server (a single vCenter Server manages DC1 and DC2) - then only a single VRMS can be used. As a result, if this VRMS is down, failover is not possible.

If there a multiple source sites and a single main shared target site and the vCenter Server and VRMS are running on the shared site (so called ROBO topology), as long as the shared site is running, failover will be possible.

If there are separate vCenter Server instances at the source site and target site, then each of them will have its own VRMS and you should be safe if the one at the source site is down.

Regards,

Martin

[jhardwood]

Hi Martin,

We have one source site with a single vcenter server, and one target site with a single vcenter server.  The replication appliance is running in the source site, replicating VMs to the target site.    If the entire source site goes down, obviously replication will be interrupted.  At that time, I will need to log onto target site and start up the target VMs.  Here is where I get confused...how will I start up the VMs if the appliance that was managing replication (and recovery?) is down (because it was running in source site)?

Thanks,

jeff

[mvalkanov]

Hi Jeff,

Are the source and target sites managed by the same vCenter Server or not?

If a single vCenter Server manages both the source and target sites, vCenter Server and VRMS must be running at the target site, in order to be able to recover VMs from the source site, in case the source site hits a disaster.

If the source and target sites are managed by separate vCenter Servers, you need to have VRMS per each of the vCenter Servers.

Currently, there is no officially supported way to recover consistent VR image of the replicated VM, if the VRMS or vCenter Server managing the target site are down.

Regards,

Martin

[jhardwood]

Hi Martin,

I apologize for my terminology, as I am new to vSphere Replication and hence may not be relaying information clearly.

My source and target sites each have their own vCenter Server.  One of the sites is our production VMware site, the other is our DR VMware site.  When we initially set this up, we built a VRMS at the source site to replicate servers to the target site.   We also setup a VRMS at the target site to replicate some VMs to the source site (we have some stuff running at target site that we want to protect also).

I guess my question, then, is: Is the VRMS at the target site "aware" of the incoming replications, such that if the source site goes down, the I can recover the VMs at the target site?    Or perhaps we never should have created a VRMS at the source site, and instead put a single VRMS at the target site and used it to configure the replications?

As you can see, I am pretty new to this feature.  I appreciate the patience and help.

THanks,

jeff

[mvalkanov]

Hi Jeff,

So you have vCenter Server A managing site A and vCenter Server managing site B.

To use vSphere Replication to replicate production VMs at hosts managed by vCenter Server A, to datastores accessible by hosts managed by vCenter Server B, you need to deploy VR appliance both in vCenter Server A inventory and also VR appliance in vCenter Server B inventory and explicitly pair them.

A single VR appliance in vCenter Server B without VR appliance at site A won't be able to handle replication data from site A.

In case of disaster at one of the sites, the VR appliance at the other site can be successfully used to perform failover. The VR appliance at site B knows enough information to perform the failover for the VMs replicated to datastores at site B.

Regards,

Martin

[jhardwood]

Hi Martin,

Excellent!  Now I feel like I am learning something.  I have indeed deployed a VR appliance in both vCenter Server A inventory and also in vCenter Server B inventory.  Can you please advise me with instructions on how to "explicitly pair them"?

Thanks,

jeff

[jhardwood]

Ok, so after reading more, I think my last question was a poor one.  I believe that since I have both VR appliances up and running and VMs replicating from Server A inventory to Server B inventory, than they are paired?  Or is there something more that I need to do? 

[Biliana]

If you have successfully configured replication from production to DR site, there is no need to pair the sites explicitly, as vSphere Replication has already done this for you "on the fly". That is -  you can either first connect both sites and configure replication between them, or just configure replication and connect the sites as part of this workflow. To be safe, you can verify that your sites are connected if you go to vSphere Replication -> Sites, select your site and click Manage tab. You should see an entry for your peer site there.

[jhardwood]

Biliana,

Thank you. I did check per your suggestion and there is indeed an entry already there, so as you stated, vSPhere Replication has done this for us as we configured sites for replication.  I am curious...when I am in the vSphere Replication "Summary" tab, both of my sites show up in the "local" tab. There is nothing in the "remote" tab.  Is that normal?

thanks,

jeff

[borislavborisov]

Hi Jeff

it is completely normal, this means your vCenter servers are using one and the same SSO server. If each of them was using its own SSO server then you would see one site in local sites grid and the other in remote sites grid.

Regards,

Bobi