Google Compute Engine VSS snapshot VM requirements

[Multidados Ti]

0down votefavorite

I am unable to find the proper documentation on what I need to activate on the windows VM to make sure my gce snapshots are indeed using VSS. Creating a snapshot with VSS enabled in pretty straightfoward on GCE - just select that option and you're done. But there is apparently no telling if you actually created a VSS-able snapshot or not. What I did, out of guesswork, is to enable the VSS service in windows, and then manually enabling VSS for all my drives on windows. Is this enough, or too much? Is there any way to validate if my gce snapshot was created with VSS as intended?

[Carlos (Cloud Platform Support)]

According to the documentation, public images newer than v20160810 are ready to work with VSS snapshots and no additional configuration is required.

I do not think there is a way to validate. Nevertheless, when you try to take a VSS snapshot of an older image it fails. You receive an error indicating that the VSS agent is not running. i.e.

"Unable to create the snapshot using VSS. The source disk may be attached to a Linux instance. You can only use VSS with a disk attached to a Windows instance. Make sure you have the latest Windows image version with the VSS agent installed."

[Amruta Gulanikar]

If the images is earlier than the one mentioned below or if there is an issue with the VSS Writers, the snapshot will fail. You will see and error code returned by the the API.

You can check the status of VSS Requester, VSS Provider and Vanadium while taking a VSS enabled snapshots using the following steps :

- Go to Windows Service Manager (run services.msc under an elevated command line windows), make sure Google VSS Agent is running. If the service state is stopped, VSS snapshot will always fail.

- The additional status can be obtained by checking the status of the Google Vss Requestor and Provider will require access to the Windows Event Log inside of the guest. The four event logs are named:  'GCE-VSS-Agent/Debug', 'GCE-VSS-Agent/Operational',  'GCE-VSS-Provider/Debug', 'GCE-VSS-Provider/Operational'

Example using Powershell: wevtutil query-events <X>, E.g. wevtutil query-events GCE-VSS-Agent/Debug

By default, only operation Log is enabled, to get more diag info, we might need to turn more logging. Example: wevtutil sl GCE-VSS-Agent/Debug /e /q

Let me know if that does not help.

Thanks,

Amruta

[Multidados Ti]

Thanks a lot for your help.
It seems everything is in order, the snapshots doesn't throw any error messages and the vss agent is running.

I'm wondering if I did not need to turn on Window's Volume Shadow Copy service, and turning on window's vss on my drives.
If that's the case I will undo those window settings.