Virtual Server Backup Trouble

If your Virtual Server VM backups are failing, here are a few places to look for the cause.

Chris: My team and I are having a bit of trouble reaching the highly valuable ability to back up live machines as you've described in this article. When we run the script this is what logs to the event viewer and why it is taking the machine offline temporarily:

Event Type: Error
Event Source: Virtual Server
Event Category: Vss Writer
Event ID: 1029
Description: The VSS writer failed to get the properties of the virtual machine vm1, since the operation did not complete in maximum allowed time. The virtual machine is allowed for Offline backup only. Check if the virtual machine vm1 is running and then retry the operation, if needed to be back online.

Another odd thing -- not sure if it is related -- but for some reason our machines .vmc files say they are Virtual PC 2004 files:

Event Type: Warning
Event Source: Virtual Server
Event Category: Virtual Machine
Event ID: 1069
Description: The "Virtual Hardware Standard" (Virtual PC 2004) in the configuration .vmc file for "vm1" was not created by Virtual Server. "vm1" can start, but some settings may be changed and some settings may not be used.

Any ideas?

After working with Jeremy, we were able to quickly determine that his two problems were related. Virtual Server was unable to confirm the VM additions or guest OS status and, in turn, was suspending the VM in order to grab a clean backup. That behavior is consistent with any VM that does not have the VM additions installed or any VM whose guest OS doesn't support VSS.

To solve the problem, Jeremy had to login to Virtual Server, create a new VM and add the old VM's disk to the new VM as an existing disk. That action created a new .vmc file that is fully compatible with VS 2005 R2. Once the VM booted, Jeremy then needed to install the latest VM additions to solve the problem.

I performed a similar test in my lab after importing a .vhd file from a Virtual PC 2007 VM. After importing the VM, the first time I tried to run the backup I received an error: 1093 -- Virtual Machine Additions on "W2K3-vpc" is out of date. Please update to the latest version of Virtual Machine Additions. Once I updated the additions, I reran the backup and it completed successfully without suspending the VM.

Since publishing a script on backing up live Virtual Server VMs, I have received a number of e-mails on Virtual Server backup troubleshooting. A few readers had run into problems with Virtual Server backup; thankfully, none so far have been related to my script.

Here are a few more tips to troubleshoot failed live Virtual Server VM backups:

  • Go to the event viewer and look at the Virtual Server event log. Look for any major or critical errors that appear. The error should help you narrow down the cause of the problem. For example, having older VM additions installed will generate an error message.
  • If you use the vsbackup.vbs script, it will create a file named CreateVSS.cmd in the folder where the script is stored. Go to the command prompt and run the CreateVSS.cmd. That will allow you to validate that the snapshot is created successfully and if an error occurs when the snapshot is created, you'll see it. If the snapshot is created, you will be able to navigate to the X drive and see its contents.
  • If you are backing up VMs using a third party backup agent, ensure that the backup product supports VS Writer. Your backup vendor should be able to tell you whether or not VS Writer is supported.
  • VSS snapshots occur at the volume level, so if select VMs are suspending during the snapshot process, that likely means that either the VM guest operating systems do not support VSS or they don't have the latest VM additions installed. VMs that support VSS should be stored on a volume separate from VMs that do not support VSS.

Hopefully these tips will help you to resolve any Virtual Server backup issues that you encounter. If I missed an error that you encountered, please post your solution as a comment to this article.

About the Author

Chris Wolf is a Microsoft MVP for Windows --Virtual Machine and is a MCSE, MCT, and CCNA. He's a Senior Analyst for Burton Group who specializes in the areas of virtualization solutions, high availability, storage and enterprise management. Chris is the author of Virtualization: From the Desktop to the Enterprise (Apress), Troubleshooting Microsoft Technologies (Addison Wesley), and a contributor to the Windows Server 2003 Deployment Kit (Microsoft Press).learningstore-20/">Troubleshooting Microsoft Technologies (Addison Wesley) and a contributor to the Windows Server 2003 Deployment Kit (Microsoft Press).

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