The Exchange Agent supports the Microsoft Volume Shadow Copy Service (VSS), a snapshot provider service only available on Windows Server 2003 or later. Using VSS, a point in time view of the Exchange database is snapped and then backed up, leaving the actual Exchange database open and available for users.
Offhost backup enables the backup operation to be processed on a Backup Exec media server instead of on the Exchange server. Moving the backup from the Exchange server to a media server enables better backup performance and frees the remote computer as well.
If the Advanced Disk-based Backup Option (ADBO) is installed on the media server, you can use the Backup Exec Granular Recovery Technology (GRT) option when you create an offhost backup for the Information Store.
The Exchange Agent snapshot does not support the following:
Due to a Microsoft Exchange limitation, if non-snapshot backups are run as part of a data protection scheme, then snapshot backups should not be run. If snapshot backups are run, non-snapshot backups should not be done.
Table: Available backup methods for Exchange snapshot versions