Error 30112 when backing up clustered Hyper-V VM

[guest]

We have a Hyper-V R2 cluster with DPM 2010 doing the VM backups at the host level. All VMs are backing up and restoring fine except two. On those VMs the following error occurs: (I changed the VM and server names)


Description: The back up to tape job failed for the following reason: (ID 3311)

There are no significant events where he tells me to look, just the same VSS events as in a successful backup.

These 2 VMs do have an extra VHD with over 200GB attached. The second one was backing up fine until recently. Most VMs have dynamically expanding disks. These 2 have them.

Error details below.

\Backup Using Child Partition Snapshot\*VM1 (*VM1*.Cluster.Domain) DPM encountered a retryable VSS error. (ID 30112 Details: VssError:The writer experienced a transient error. If the backup process is retried,
the error may not reoccur.
(0x800423F3)) Check the Application Event Log on Clusternode2.domain for the cause of the failure. Fix the cause and retry the operation.
For more information on this error, go to http://go.microsoft.com/fwlink/?LinkId=132612.
\Backup Using Child Partition Snapshot\*VM2* (VM2.Cluster.domain) DPM encountered a retryable VSS error. (ID 30112 Details: VssError:The writer experienced a transient error. If the backup process is retried,
the error may not reoccur.
(0x800423F3)) Check the Application Event Log on Clusternode1.Domain for the cause of the failure. Fix the cause and retry the operation.
For more information on this error, go to http://go.microsoft.com/fwlink/?LinkId=132612.

[guest]

The retryable VSS error can also occur if there is a problem with one of the VSS writers within the VM itself (e.g. writer in a failed/retryable state). Have you executed the "vssadmin.exe list writers" command within the problem VM?
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[guest]

It could be the SQLServerWriter Service. Can you turn off the SQL writer service and take a backup to assert/eliminate this being the faulty writer. Are there any additional events in the application event log of the VM where the SQL server writer service is runinng?


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