Description
For databases using mirroring. This wait type accumulates during mirroring activity. It is used internally so it is not formally documented by Microsoft. Moderate values tend to not be problematic but if high values are experienced then investigating other mirroring waits are recommended. Please note that database mirroring is a deprecated feature and could be removed in an upcoming release. Investigation into other high availability and disaster recovery solutions is recommended
Resolved by
DBAs and Developers
Suggested solutions
- If transaction on the principal are being delayed (because of high waits) consider switch the mirror mode to asynchronous
- Use Windows Performance Monitor to check network latency and whether the connection is over-utilised
- Ensure network devices have been configured correctly
- Consolidate transactions from row-by-row statements to batch processing. Batch processing generate less messages
- Unnecessary index maintenance must be sent across to the mirror (unnecessary messages). Remove any unused indexes from the principal
Additional research
Should you ignore DBMIRROR_DBM_MUTEX?
Troubleshoot Database Mirroring Configuration
Database Mirroring Best Practices and Performance Considerations