Virtual Server Backup Trouble
If your Virtual Server VM backups are failing, here are a few places to look for the cause.
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
. 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
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.
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
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on "W2K3-vpc" is out of date.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
- 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.
Chris Wolf is VMware's CTO, Global Field and Industry.