Exchange 2007 Mailbox Database Size Reduction That Seems To Good

Posted on 2009-04-30
Last Modified: 2012-06-27
The 2007 Email system we currently use has been here since the start and we upgraded from 2003 years ago.
I have 3 db's that separate users based on job level. When we first determined the size of all three mailbox db's the total was around 160GB (removal of disconnected boxes really helped)
but to further reduce the mailboxes I have created two new storage groups. However what concerns me is before I moved the mailboxes to the new s.groups, the db size was 120gb - after I created the new and moved everyone the new db is just 85gb - thats a huge reduction.
That was a week ago and no one has complained. We do have a GP that forces cached mode on the users but nothing else.
Is this a normal reduction? Have I made a mistake and the cached mode is covering it up?

thanks for the help
Question by:DFCRJ
    LVL 15

    Accepted Solution

    Cached mode won't affect the size of the databases, it just saves a copy locally.

    When you moved them, did the block or cluster size on your drives change?

    If the database had not been growing for a while, you probably had a lot of whitespace from deleted/purged mailboxes that hadn't been cleaned up by an offline defrag.  Moving the mailboxes to new db's would have eliminated that.
    LVL 6

    Expert Comment

    Cached mode should have nothing to do with it. By moving to a new database, you're leaving behind the whitespace and retained deleted mailboxes, etc.
    LVL 24

    Expert Comment

    When you delete an item from your mailbox, the item will be kept on the dumpster for as long as configured for your mailbox or for the mailbox database to which your mailbox belongs. The default deleted item retention time in Exchange 2007 is set to 14 days. Users are able to recover items from the dumpster using both Microsoft Office Outlook and Microsoft Outlook Web Access. As administrator you need to keep in mind however that when you move a mailbox from one mailbox database to another mailbox database, that the content of the dumpster is not moved for that mailbox and therefore lost.

    This explains why the size is less. So, if you are having a retention setting of 30 days, that's too much of data that is lost.

    Author Closing Comment

    Thank you all for you answers. They helped a ton

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