This article refers to Microsoft Exchange Server 2010 and 2013; note that circular logging is disabled by default in Microsoft Exchange 2010 and 2013.
circular logging is designed to save storage on your Microsoft Exchange Server by preventing transaction logs from building up on the Server. This is achieved by creating and writing to a total of four transaction log files. Once the fourth log is full, it cycles back to the first log and overwrites it, creating a logging cycle referred to as circular logging. Once the first log is full, it then moves on to overwrite the second, third, and fourth, and then cycles back to the first log. The assumption is that by the time the fourth log is filled, the first log is committed.
These transaction logs are saved for use when restoring data. If circular logging is enabled, this is not possible as you are able to restore only to the last full backup as the transaction log sequence is not consistent making it unreliable.
If you are unable to complete a Smart Backup or Log Backup of your Microsoft Exchange Server, you can enable circular logging. In this case, an error similar to the following displays either in the Barracuda Backup web interface or in a Barracuda Backup report:
Incremental backups cannot be performed while circular logging is enabled for
<Exchange Storage Group>. Disable circular logging to perform incremental backups.
Disable circular logging in Exchange 2010
Use the following steps to disable circular logging for the Exchange Storage Groups on the Exchange Server 2010:
- Log into the Exchange Server as the administrator, and open the Exchange Management Console (EMC).
- In the console tree, expand Organization Configuration, and click Mailbox.
- In the result pane, click the Database Management tab and click Properties below the storage group database.
- Click the Maintenance tab, and turn Off Enable circular logging. Click OK to close the Properties dialog box.
- Restart the Microsoft Exchange Information Store service or dismount and then mount all of the databases in the storage group.
Disable circular logging in Exchange 2013
Use the following steps to disable circular logging for the Exchange Storage Groups on the Exchange Server 2013:
- Log into the Exchange Server as the administrator.
- In the left pane, click servers, and then click databases at the top of the page.
- Click on the Mailbox Database, and click the edit () icon.
- In the Properties window, click maintenance, and turn Off Enable circular logging.
- Click save to close the Properties window.
- Click on the Mailbox Database once again, and click the more () icon.
- Click Dismount database. Once the view refreshes, click the more () icon once again, and click Mount database.