MSSQL: To many databases in the VSS backup at once

Operatingsystem

Windows

Software

7.5.0.0 and higher

Error Message

Cannot start shadow copy, reason = The writer operation failed because of an error that might recur if another shadow copy is created. (VSS_E_WRITERERROR_NONRETRYABLE)

Cause

The error message is returned by MSSQL VSS writer, suggesting that there were insufficient number of worker threads configured on the MSSQL Server to support the backup all databases selected for backup.
A MSSQL Server databases backup job using VSS requires three worker threads per database.
For example, a 64 bit MSSQL server with 4 CPUs is automatically configured with 512 work threads, which implies that the maximum number of databases that can be selected for backup is 170.

Please refer to the Limitations and Restrictions section in the following article for more details:
Configure the max worker threads Server Configuration Option

Solution

To resolve this issue, either:
1. Create additional backup sets (to be performed at different time) for the excess databases.
or
2. Increase the maximum number of worker threads on the MS SQL Server.

To configure the max worker threads option:

• In Object Explorer, right-click a server and select Properties.
• Click the Processors node.
• In the Max worker threads box, type or select a value for the max worker thread.

For more details, refer to the following article: Configure the max worker threads Server Configuration Option