Exchange Server transaction logs truncated after backup

Resolving The Problem

Tivoli Storage Manager completes a full backup and reports the backup is successful to Exchange. It is then the responsibility of Exchange to perform the actual log file truncation. You should see evidence of this notification to truncate logs in the Windows Event log.

The following sequence is followed:

• Start the backup of the Exchange database, single or multiple databases.
• When the backup has completed successfully, Tivoli Storage Manager will notify the Exchange Server that backup is complete for the specified database and that it may now do whatever other functions it needs to do against.

• If there are multiple databases to backup, it will notify the Exchange Server after each successful backup.

• With Exchange Server 2007, all databases within a storage group must be mounted at the time of the backup operation. If any database within a storage group is not mounted, the storage group is skipped and therefore, not backed up. In addition, the transaction logs will NOT be truncated.
• With Exchange 2010 and higher, especially set up in a Database Availability Group (DAG), the log truncation can seem delayed because Exchange must make sure all log updates are sent and committed in all copies (active and passive) before it truncates the logs.