In Exchange 2010, white space is not reclaimed in scenarios where objects are deleted or truncated during Online Defragmentation. This lack of whitespace reclamation includes scenarios with Enterprise Vault where message items are modified into shortcuts, or where items are deleted post-archiving. Customers will notice Exchange database sizes continuing to grow, despite object deletion or truncation having occurred.
Microsoft have resolved this issue and the hotfix is available on request or can be installed as part of Exchange Server 2010 Service Pack 3. . Please review the following Microsoft knowledge article for more information:
An Exchange Server 2010 database store grows unexpectedly large
Note: This will fix any new data added but not clean the dirty pages or whitespace from preexisisting databases.
For more information please review the following Symantec blog article:
Exchange 2010 whitespace reclamation
This issue applies to all Enterprise Vault versions that support archiving from Microsoft Exchange 2010.