How to troubleshoot Hyper-V VSS backup errors
One of the more common situations which we came across working for various backup vendors is the massive number of times systems have problems with Hyper-V VSS backup errors. We’ve previously written about VSS if you’re looking for more background.
Microsoft has made it easier to determine what the cause is with each release of new operating system. Server 2008 was full with generic errors which didn’t give anyone much hope of effectively troubleshooting; whereas Server 2012 and Server 2016 identifies a particular guest that’s generating the error quickly and easily.
The easiest and most effective way we’ve found to solve Hyper-V VSS backup errors is outlined below.
Check the Hyper-V VSS writer
Hyper-V best practice according to Microsoft, the Hyper-V VSS writer is used to take a consistent snapshot of each of the guest machines.
Unfortunately; if the Hyper-V VSS writer isn’t functioning correctly then it’s going to be unable to take a complete snapshot properly – resulting in errors.
Fortunately, it’s easy to see if the Hyper-V VSS writer is in a failed state. All that needs to be done is to run the following command from a command prompt that’s running as Administrator:
vssadmin list writers
As a result; this will provide an output that shows basic information for all VSS writers which are running within the operating system. An example of what you’d see for the Hyper-V VSS writer is in the screen shot below:
If the information provided is anything other than State: Stable or Last Error: No error then it means that the Hyper-V VSS writer isn’t working properly.
In addition; the most effective way to clear errors with the Hyper-V VSS writer is to reboot the machine; as this will allow the machine to clear everything.
Check Event Viewer on the Hyper-V host machine
As with most Windows functions, VSS logs in Event Viewer. To begin; you’ll firstly need to open Event Viewer using the steps outlined below:
- Press the Start button.
- Click Control Panel.
- Double click System and Maintenance.
- Select Administrative Tools.
- Double-click Event Viewer.
Once you’re in Event Viewer, you can find applicable errors to your backup by opening:
Application: browse to Windows Logs > Application.
System: browse to Windows Logs > System.
Hyper-V VMMS: browse to Applications and Services Logs > Microsoft > Windows > Hyper-V-VMMS
In many cases, a guest machine could be listed with VSS snapshot errors during the backup process. In the screen shot below, a guest machine named Win10 caused the problem specifically.
Investigate the guest machines themselves for potential errors
As mentioned above it’s very common for guest machines to cause the entire VSS snapshot process to fail. If that’s the case, it’s a good idea to check the guest machines for errors as well.
The best place to begin is by logging in and checking Event Viewer on the guest machine itself. Specifically looking at the Application and System logs (using the same steps in the section above).
Other tools to help identify Hyper-V VSS backup errors
Some backup vendors utilize Microsoft VSS to take snapshots as part of their backup process. Since these are common types of issues that they encounter; they’ve provided tools which can help diagnose, identify and even fix VSS related problems within the system.
Take the hassle out of troubleshooting Hyper-V VSS backup errors
TestMyBackups has many decades of collective experience troubleshooting VSS errors in general. We can help solve the errors for you; as well as guarantee the successful backups you have are able to recover by utilizing our testing platforms. Check out our available service plans.
Have you experienced issues with VSS when backing up Hyper-V? Feel free to mention them in the comments below, or let us know directly.