VSS Snapshots

[gingerdazza]

I'm interested to hear what everyone's strategy is when it comes to doing VSS backups, specifically whether most people always enable VSS based backup on Windows VMs, or whether they pick and choose the VMs on which they do VSS backup (i.e. AD, SQL, Exchange, etc.)? Why would you choose NOT to do VSS aware backup on a windows VM? Stun?

Would welcome people's thoughts.

Thanks

[nmdange]

Disclaimer: my environment is Hyper-V not VMWare so I don't know if "Stun" is a big issue with VMWare that doesn't occur in Hyper-V.

I always enable VSS for everything, even for VMs besides AD/SQL/Exchange, you still need VSS to ensure a file-system consistent backup. The only time I have ever disabled it is in the case where a VM's VSS is broken and the backups are failing with a VSS error. I'll switch to crash-consistent temporarily just to get something.

[DeadEyedJacks]

Not all Windows applications are VSS aware.
Some will crash when a VSS snapshot of the VM is taken, others just don't quiesce and won't be transactional consistent.
We have two such applications out of a catalogue of five hundred applications.
Know your service catalogue and test the outliers outside production environment.