Mike W asks:
“When backing up a virtual machine, what files need to be backed up?”
”Do the virtual servers need to be down for the backup?”
”What considerations need to be made when doing a ‘Disaster Recovery’ of a host server?”
Well Mike, you sure do ask a lot of questions. And I don’t think I can do this very big topic justice with just this one blog response. So let me give you my thoughts, and hopefully weave in some links to good resources that you can use to learn more about virtual machine backup best practices. (And I’m sure I’ll leave some awesome method or idea out of this.. so if you readers have other best-practices or helpful hints, please be sure to share them in the comments!)
Good and Cheap – Just copy the virtual machine’s files to another location. NOTE – in this case the virtual machines DO have to be stopped. The .VHDs, snapshots, and the machine’s configuration all will need to be copied; and they might not all reside in the same place. (Check your machine’s settings to find out where they are.)
The pros are that this doesn’t cost anything extra. But the cons are that you have to do this manually (or scripted), and it’s usually ruled out anyway due to the necessity for the machine to be turned off at the time.
An even better method here, as long as your machines are already turned off, is to script and launch an export of the virtual machines. This will put all of the required files for each virtual machine into one easily restorable (importable) folder. Ben “Virtual PC Guy” Armstrong describes this process on his blog in two parts: Part 1, and Part 2.
Better (and still Cheap) – Use Windows Server Backup. This is good because in some cases you can take advantage of Volume Shadow Services and actually back-up a running virtual machine. (NOTE: You have to register the Microsoft Hyper-V VSS writer with Windows Server Backup. See this KB article for a description on how to do it.) Pro: It’s available for no additional cost. Con: It still may require your machines to be turned off if they’re older non-VSS-aware operating systems. Note that there are additional requirements, such as the Integration Services being installed and with the backup integration service not disabled, the virtual hard disks be NTFS-formatted basic (not dynamic) disks, and more.
What are the rest of you using to back up your Hyper-V based virtual machines?