SQL VSS Backup problems

[kubimike]

Hi all, I figured I'd share this here since it took awhile to figure out. I had a job that was failing because the VSS writer was having an issue. The fix was not so simple, basically I had too many databases (174 to be exact) that didn't have enough worker threads to make the backup happen. I had a microsoft ticket and a Veeam ticket open. Microsoft was throwing the kitchen sink at it for weeks with no solution. I came across this post http://www.thegurleyman.com/sql-max-wor ... databases/ which fixed the issue. I hope this helps someone out there. For reference I set my value at 4096

Here are a few of the errors I got :

Code: Select all

[color=#0080BF]4/25/2019 4:49:34 AM :: Processing Error: Failed to prepare VM for processing: Failed to call RPC function 'Vss.Unfreeze': Error code: 0x80004005. Failed to invoke func [Unfreeze]: Unspecified error. Unfreeze error: [Backup job failed. Cannot create a shadow copy of the volumes containing writer's data. A VSS critical writer has failed. Writer name: [SqlServerWriter]. Class ID: [{a65faa63-5ea8-4ebc-9dbd-a0c4db26912a}]. Instance ID: [{06a18779-61de-4f03-bd6e-274a4feedf77}]. Writer's state: [VSS_WS_FAILED_AT_PREPARE_SN  [/color]


[color=#0080BF]BackupIoRequest::ReportIoError: write failure on backup device Operating system error 995(The I/O operation has been aborted because of either a thread exit or an application request.).
A VSS writer has rejected an event with error 0x800423f4, The writer experienced a non-transient error.  If the backup process is retried,
the error is likely to reoccur.
. Changes that the writer made to the writer components while handling the event will not be available to the requester. Check the event log for related events from the application hosting the VSS writer. 

Operation:
   PrepareForSnapshot Event

Context:
   Execution Context: Writer
   Writer Class Id: {a65faa63-5ea8-4ebc-9dbd-a0c4db26912a}
   Writer Name: SqlServerWriter
   Writer Instance Name: SQL Server Code-Named 'Denali' CTP2:SQLWriter
   Writer Instance ID: {06a18779-61de-4f03-bd6e-274a4feedf77}
   Command Line: "c:\Program Files\Microsoft SQL Server\90\Shared\sqlwriter.exe"
   Process ID: 1164[/color]

[HannesK]

Hello Mike,
thanks for sharing this with the community. Highly appreciated!

Could you maybe post the Veeam case number for reference that we can improve our support answers?

Thanks,
Hannes

[foggy]

Old trick, but still thanks for sharing.