Defining VSS transient errors
The client considers several Volume Shadow Copy Services (VSS) errors to be transient. Transient errors are network errors or drives that are temporarily misbehaving that might require backup recovery.
When one of these errors occurs, the client will, by default, retry the VSS backup process three times at 30-second intervals. The number of retries and retry intervals can be configured by using two test flags (TESTFLAG SETVSSMAXRETRY and TESTFLAG SETVSSDELAY). The client considers the following VSS errors to be transient:
- VSS_E_MAXIMUM_NUMBER_OF_VOLUMES_REACHED
- VSS_E_SNAPSHOT_SET_IN_PROGRES
- VSS_E_MAXIMUM_NUMBER_OF_SNAPSHOTS_REACHED
- VSS_E_PROVIDER_VETO VSS_E_UNEXPECTED
- VSS_E_FLUSH_WRITES_TIMEOUT
- VSS_E_HOLD_WRITES_TIMEOUT
- VSS_E_WRITERERROR_TIMEOUT
- VSS_E_WRITERERROR_RETRYABLE
- VSS_E_WRITERERROR_OUTOFRESOURCES
- VSS_E_WRITER_NOT_RESPONDING
- VSS_E_VOLUME_IN_USE
- VSS_E_PROVIDER_IN_USE
- VSS_E_UNEXPECTED_PROVIDER_ERROR
- VSS_E_UNEXPECTED_WRITER_ERROR