All Full VM backups of the Sharepoint virtual machine failed with the following error:
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))
Running a synchronization job with consistency check gave the same error.
Backups of other VMs worked perfectly.
In the DPM log files on the Hyper-V host I only found the same error code as in the DPM alert.
In this case, the logs weren’t really helpful.
I logged on to the Sharepoint server, opened an elevated command prompt and ran:
vssadmin list writers
A lot of writers, both system and SharePoint writers, where in state Waiting for Completion.
Rebooting the server made the writers Stable. Until I retried the backup job.
All writers went to exactly the same state as before the reboot.
I opened event viewer and noticed a lot of SharePoint related errors.
One of the IT guys at the customer site had also told me the SharePoint search didn’t work.
Because SharePoint vss writers were also in a error state I decided to look closer into the SharePoint issues.
Alerts in event viewer looked like this:
The mount operation for the gatherer application 5bfe200c-6fbe-4eef-811f-487d7b875766 has failed because the schema version of the search administration database is less than the minimum backwards compatibility schema version supported for this gatherer application. The database might not have been upgraded.
This led me to the following blog post about SP1:
SP1 installation requires two steps! Running the update executable, which updates the binaries, and running an additional command which updates the database etc!
By running the following command in an elevated SharePoint PowerShell prompt I noticed the upgrade wasn’t executed correctly.
I completed the upgrade with the following command:
PSConfig.exe -cmd upgrade -inplace b2b -force -cmd applicationcontent -install -cmd installfeatures
Rebooted the server and retried my backup! It worked without any issues!
My Virtual Machine Backup failed because of an issue on Sharepoint application level!
Sharepoint issues were blocking VM backups. The sharepoint application backups were running fine the entire time.
I have said it before: it’s not always a DPM issue. A lot of people find it easy to blame DPM.
But I have learned the most issues are because of issues on application level!
Make sure your application runs fine when troubleshooting backup failures!