FT (Fault tolerance) protected virtual machines are among the most awesome features VMware allows today. VMs with zero-downtime are tempting, and even with 1 vCPU limit, there are use cases where you can take advantage of them.
Another limit however has always discouraged its usage: you cannot take snapshots. Every backup solution based on VMware VADP libraries use snapshots, and Veeam is no different. So, it’s not possible to backup FT VMs via snapshots.
Is there any different method?
So far, best practices always suggested to use FT only on really needed VMs, both because of snapshots problems, both for the additional load on the infrastructure, and also for the dedicated network you need to have to sync primary and secondary VM.
To backup them, we all have used classic solutions with agents deployed inside the Guest OS, just like we would have done for a physical server.
During the last VMworld US 2012, VMware showed the future version of FT, that will allow multi-processors and snapshots; this article maybe will be obsolete in the future. But while the new FT version is not available, we have to deal with the snapshots problems.
There could be another way for doing backups? Maybe yes. Or even two ways!
If you take an FT-enabled VM, and you disable FT for a while, you will find out you can then snapshot it, and so do a backup. You are obviously “cheating”, since during backup operations this VM is NOT protected by FT. There are situations where 1 hour of FT non protection is acceptable, maybe because you do it during non working hours, while is other situations you cannot allow not even a single minute of non protection. This is up to you.
If you can disable FT for a while, then you can automate the whole operation with three PowerShell scripts. Cody Bunch has already showed in this article how to disable and enable FT via Powershell. You then only need another Powershell script, to run Veeam backup, and you will only need to use this cmdlet
Start-VBRJob -name job_name
Once backup is complete, you will then run Cody’s code to re-enable FT.
If you have HP LeftHand and Veeam Backup 6.5
When Veeam Backup and Replication 6.5 will be available (4th quarter of 2012), HP LeftHand owners will have another workaround by leveraging SanSnap Restore. I already described this feature here. I also saw a demo at VMworld US 2012, and is fascinating:
Basically, it uses the best of two solutions: fast san-based snapshots, avoiding san restore complexity. Why it can be useful to backup FT VMs? Probably you already understood where I’m headed: you can use SAN snapshots to bypass vSphere snapshots problems, create a crash consistent copy of that VM, and then be able to restore it.
There are limits in this solutions, different from the first method but nonetheless less important: the worst is snapshots are saved on the same storage where VMs are executed. If you loose the storage, you loose both VMs and their copies. Your due diligence should plan also standard backup to be safe. For Veeam guys reading this, a suggestion for further improvements of SanSnap: the ability to extract a backup copy directly from the san snapshot ;).