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Backup Exec Exchange 2010 Full vs Incremental Log Truncate

Created: 15 May 2013 | 5 comments

Currently we have BackupExec performing a full Exchange 2010 backup (about 400GB) nightly.  This is beginning to run way too long and start to eat into our production time.  I am exploring the potential for running incremental backups nightly with a weekly full backup.  However, i am noticing that the incremental backups do not seem to truncate the logs.  I did some research and found some forum articles here indicating that only Full backups truncate Exchange logs.

However, MSDN indicates that incremental backups are supposed to truncate the logs:

Why does Backup Exec not conform to this apparent Microsoft standard?  Or, if it does, what are some possible reasons our full backups truncate the logs but incrementals do not?

Operating Systems:

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Twinkle's picture

Exchange truncates all committed transaction logs once backup exec notifies that backup is successful.Are you using DAG by any chance ?As if there is any issues with your DAG and log replications are not fully up to date they they cannot be truncated.

Are your log files getting truncated after the full back ?

The logs are not removed immediately ,around the same time the backup finishes , it does take some time.

VJware's picture

Is circular logging disabled ? Ensure AOFO is not enabled in the backup job properties.

Any errors in the Exchange event viewer ?

Sush...'s picture

Hello Steve,

   you may refer to the following technote : A Exchange Full backup does not Truncate logs and Exchange event shows No log files can be truncated

Also is he Exchange server a VM machine? Refer to the following : Changing the log truncation setting of the Symantec VSS Provider



Hope this piece of Information Helps you... and if it does then mark this response as Solution....!!!

stevezemlicka's picture

This is not a part of a DAG. The logs are truncated with a full backup.

Circular logging is not enabled.  AOFO is enabled and set to automatically select snapshot technology.

I do see an Event 6

Cmdlet failed. Cmdlet Get-Mailbox, parameters {Identity=backup}.

though this event does not appear during or after the incremental backups that fail to truncate the logs.

Sush, We do not have issues related to full backups not truncating the logs nor do we get the error related to the first article.  The second article seems to pertain to disabling truncating...though this is a Hyper-V VM.

When i modified the backup, i simply added an incremental step to the full backup we already had implemented.  However, it did give me a notification that a full backup should be performed since the modification.  I almost wonder if the logs weren't truncated because backup exec didn't send the completed successfully flag to Exchange since a full backup hadn't been performed since the job modification.  Even though we just modified the job that included the successful full backup from the night before.  Does that sound feasible?

BTW, after removing the incremental step and going back to full backups, the logs are again getting truncated as expected.

VJware's picture

Would recommend to disable AOFO in the job properties for Exchange backups.