When a mail file with an attachment is addressed to 2 or more of your 
exchange server clients, the attachment is stored only once and, with 
your NetBackup setting, backed up only once.

If you've a lot of multiple-recipient mail (same exact, came into your 
server in one blob, mail) with attachments, this setting can help. My 
exchange server folks think they do this a lot, but in practice I see 
little or no effect on backup/restore times.

Mailbox backup is snail-slow compared to DB backups.

cheers, wayne

Kilpatrick, Mark wrote, in part, on 4/26/2006 11:19 AM:
>
> What happens if I enable the option of ?single instance backup for 
> message attachments? under exchange field of client properties. I am 
> currently using mailbox backups but they take a long time. What will 
> be different in a mailbox backup if I enable this option? How will 
> backup time and restore time of mailboxes be effected.
>
> Single Instance Storage is used by our exchange server.
>
>