But I only want to restore a single mailbox...

I'm using DPM to backup my Exchange data and I want to restore a single mailbox only. Is that possible?  This is a pretty common question at the moment and the answer is of course Yes.  However DPM takes volume snapshots using VSS and so you will need to restore an entire volume set (i.e. database and transaction logs) to a point in time, to a recovery storage group or recovery server, and then extract the relevant mailbox data from this restored database.  There is a good article that was posted recently on this subject - 'Recovering Mailboxes'.

It is of course essential to have to the ability to recover entire mailboxes or individual items within a mailbox, however if this should be a last resort regardless of the backup solution in place.  Traditional 'bricks-level' type backups are expensive in terms of performance and storage and are not very common in my experience because of these limitations.  If you are restoring mailboxes regularly then consider planning to increase the deleted mailbox and item retention periods but probably the most successful approaches will be to try to talk to the people generating the requests..  What are they doing wrong? Do they understand what the request entails for support staff? Could they be charged directly for support staffs time for each request?  There is likely to be a proactive approach to ensuring that these types of requests are reduced...

In my opinion a good messaging design should incorporate a backup solution that is only ever used for firedrills...