I’ve spent much of the last 6 weeks either thinking about or working on Hyper-V Replica. The topic of where to do backups came up in conversation. Normally it is advised to do a backup in the primary site and replicate the data offsite, ideally to the DR site where it will be readily accessible – storing it in an offsite warehouse that it under the same 3 metres of water as the production site is pretty useless!
Before you ask: Replication is not backup. Replication gives you current/recent copies of VMs/data. Backup gives you an archive of days, weeks, months, or even years. And your need to retain archive data doesn’t disappear (practically or legally) just because you have invoked your DR plan.
So in the conversations, one of the guys wondered if maybe it would be more efficient to do the backup in the DR site. That would mean running backups of the replica virtual machines that are created and maintained by Hyper-V Replica. An interesting concept!
Backing up or restoring the Hyper-V replica is not supported.
Due to the inner workings of the Hyper-V replication architecture which may be in progress during the time of a DPM backup, there can be no guarantees of a successful backup or restore of virtual machines that reside on the Hyper-V Replica server.
My guess is that the HRL replay which is updating the replica VHDs every 5 minutes would prevent a reliable backup in the DR site.
That means that you should (and can) continue to backup the source virtual machines in the production site, and continue to replicate your backup offsite to the DR site.
For the wise-asses out there (you know who you are), let’s be clear:
- Yes, you can still use Hyper-V Replica
- Yes, you can continue to backup replicating VMs in the production site
- Yes, your backup tool might be able to backup replica VMs in the DR site, but that doesn’t mean that this is supported. Don’t come crying to me (or anyone else) if you ignore this statement and your “engineering” bites you in the ass.
- Non-replica VMs that are running on the DR site hosts can be backed up in a supported manner