Question : Exchange 2003 Enterprise Offline Defrag

We have 10 x Exch 2003 Enterprise servers with approximately 4 Storage Group and 3 / 4 mailbox stores for each.

We have just implemented a recipient policy that deletes all deleted items after 30 days, Inbox after 90 days and sent items after 90 days.

At the moment we have huge amounts of white space, so I feel this is the time to start looking at Offline defrags to reclaim the space and shrink the EDB / STM files.

My initial thoughts were to approach this at the mailbox store level, rather than the storage group, and was hoping we can do an offline defrag.  I am loathe to create extra storage groups and move the mailboxes into those as this would in my mind grow the database due to the loss of single instancing.

Does anyone have any best practice recommendations, and possible documentation / article links to support any answers?

Answer : Exchange 2003 Enterprise Offline Defrag

Your fear of SIS loss is actually unfounded as well.
http://support.microsoft.com/kb/175481

Simon.