I have one VM that won't backup without error. I rebooted the VM and we're still getting the error. I'm not sure what to look at on this specific server, I'm going to check the event logs next.
Here's the error:
2/22/2013 10:05:04 AM :: Failed to prepare guest for hot backup. Error: VSSControl: Failed to prepare guest for freeze, wait timeout 900 sec
This is a Microsoft VSS error so you'll need to look in the Windows event log for further details as to why the systems was unable to perform a VSS freeze. If you want to get a backup of this VM in the interim you can change the job settings to treat a VSS failure as a warning rather than an error. This will give you a "crash consistent" backup, which I'd rather have than no backup at all.
Probably the most common issue I see for VSS is lack of space on the system drive of the VM, but there are so many things it could be that it's almost impossible to just guess. Based on the VM name this is a SQL server so it's possible it was simply too busy to find a period to "freeze".
Jonathan, please kindly open a support case and provide case ID here, as it is advised when posting about technical issues (explained when you click New Topic). Thanks.
Looking instead at the time of the replica job, is 10 AM so during business hours, could it simply be the SQL server is too busy with I/O activity to correctly reply to a VSS freeze before the timeout? There are some elements that can interfere with VSS, among them:
- lack of free disk space
- high I/O activity
- high number of file fragments
- conflicting VSS providers installed by previous softwares
And others. Also, take a look at this article as a starting point, it also has links to other suggestions:
Yes, I agree with Luca, I've seen these kind of errors when SQL Server VM was too busy and VSS writer simply couldn't prepare all applications for a freeze operation. Try re-scheduling this job on a different time to see if this resolves the issue or not.