VSS writer, DPM 2007 VM backups, vhdmount.exe

Thread view:

Enable EMail Alerts

Start New Thread

Thread rating:

Brit - 24 Jul 2008 20:35 GMT

Today I started some tests with protecting VMs using DPM 2007 and need some
help understanding the errors I'm getting:

The VSS writer for Virtual Server failed during the PostBackup phase, during
the mounting of disk
\\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy8\VM\DAVUTIL1\DAVUTIL1.vhd for
virtual machine DAVUTIL1. The disk did not come online within 5 minutes.
Confirm that the vhd mount driver in installed correctly and is able to mount
virtual hard disks.

After doing some research on this topic and applying hotfixes that are
relevant to this issue, I think I'm running into an issue whereby the vhd is
mounted with the "undo" switch, which results in needing twice the space as
the original vhd to mount. If there is not enough physical disk space to
accomodate mounting the vhd, the VM backup will not continue.

If this is the case, there are of course two questions:

1. Where are VHDs mounted during this process?
2. Is the location VHDs are mounted configurable?

Thanks,
Brit

Reply to this Message

Alexander Ortha [MS] - 25 Jul 2008 02:48 GMT

Hello,

What versions of Virtual Server and DPM do you use?

Signature

Mit freundlichen Grüßen / Kind regards - Alexander Ortha (Microsoft)

German Virtualization Blog
http://blogs.technet.com/germanvirtualizationblog/default.aspx

This posting is provided "AS IS" with no warranties, and confers no rights.

> Today I started some tests with protecting VMs using DPM 2007 and need
> some
[quoted text clipped - 25 lines]
> Thanks,
> Brit

Reply to this Message

Brit - 25 Jul 2008 14:53 GMT

VS2005R2 SP1 with hotfix 948515 (1.1.629.0 EE R2 SP1)
DPM2007 with update Rollup 3 (2.0.8107.0)

...and nevermind about the very first two questions...I figured those out,
but:

A little further investigation revealed that the problem stems from the fact
that the VM has a basic disk and a dynamic disk. I can mount the dynamic
disk, but I have to "import foreign disk" in Disk Management on my Virtual
Server host.

This leads me to believe that the automated process of DPM using vhdmount
remotely won't work since it requires an acknowledgement in Disk Management
that the dynamic disk can be imported.

So...

1. What is the official word on protecting VMs with dynamic disks?
2. In figuring this out, I crashed my Virtual Server each time the dynamic
vhd attempted to be mounted. All the VMs stopped responding, and the server
itself had to be bounced to regain control. Fortunately the first time this
happened, I got wise and shut off the other VMs so they would not get beat up
in case it happened again.
3. The other issue was that the vhdstor.inf device had not been installed.
Seems like this should have been a part of the SP1 installation.

Anybody know about this?

> Hello,
>
[quoted text clipped - 29 lines]
> > Thanks,
> > Brit

Reply to this Message