Hello,
I am assuming you are doing it cause the size of the database has grown a lot.
You might want to do the following(for Backup Exec 2010): Removing entries from the audit log
You can also use the Backup Exec Utility(BEUtility):
1. Launch the BEUtility (default location: C:\Program Files\Symantec\Backup Exec\BEUtility.exe)
2. Expand Known Computers and then select All Backup Exec Servers.
3. In the right window pane, right-click the Backup Exec media server, and then click Compact Database.
4. The Operation Progress dialog box will appear, indicating the process of compacting the database.
5. On completion, click Close.
6. Close BEUtility.
(The above steps are taken from this link.)
