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Will moving a mailbox to a new storage group trim whitespace? RRS feed

  • Question

  • We have implemented an email archive system and while this has removed a lot of the data from my storage groups, they remain the same size. Would creating a new storage group and moving the mailboxes over trim the whitespace? 
    Tuesday, March 22, 2011 10:08 PM

Answers

  • Nothing will trim the whitespace except for offline defrag. Moving the mailbox to another DB will not trim the whitespace. What you can do is create another database and move your users to the new database since your mailbox sizes are much smaller after the archive. Then when all users are moved, just delete the old database.

    Your only other option is to do an offline defrag.


    James Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com
    • Marked as answer by JasonBeckett Tuesday, December 20, 2011 1:58 AM
    Tuesday, March 22, 2011 10:34 PM
    1. What version of Exchange are you using
    2. If you mean moving the mailbox to another database then Yes it may use less space in the new target database, however it may use more as well i.e. in Exchange 5.5 - 2007 there is Single Instance Storage, i.e. if an item is sent with a 1MB attachment to 100 people in the same database then the attachment only takes up 1MB since all 100 users point to that instance of the attachment.  However, if you move that user to a new database then that message attachment is extracted and placed into the new EDB.  So in short you may gain in one area and lose in others so that in the end mailbox size may end up being larger or smaller depending upon how much data was removed vs affected by SIS.
    3. That said James is correct in that the OLD message store will not change size when you move a mailbox out to another database UNLESS post move you defragment it
    4. He is also correct that your best move to avoid downtime would be to move all users to a new DB and then drop the old DB when done.  Actually I would take the old one offline for a day or two to ensure nothing was missed and then when you are comfortable delete the old DB.
    5. Also if you do this ensure that you modify you backup product to stop backing up the old DB and start protecting the new DB

    Troy Werelius
    www.Lucid8.com
    • Marked as answer by JasonBeckett Wednesday, March 23, 2011 12:26 AM
    Tuesday, March 22, 2011 11:24 PM

All replies

  • Nothing will trim the whitespace except for offline defrag. Moving the mailbox to another DB will not trim the whitespace. What you can do is create another database and move your users to the new database since your mailbox sizes are much smaller after the archive. Then when all users are moved, just delete the old database.

    Your only other option is to do an offline defrag.


    James Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com
    • Marked as answer by JasonBeckett Tuesday, December 20, 2011 1:58 AM
    Tuesday, March 22, 2011 10:34 PM
    1. What version of Exchange are you using
    2. If you mean moving the mailbox to another database then Yes it may use less space in the new target database, however it may use more as well i.e. in Exchange 5.5 - 2007 there is Single Instance Storage, i.e. if an item is sent with a 1MB attachment to 100 people in the same database then the attachment only takes up 1MB since all 100 users point to that instance of the attachment.  However, if you move that user to a new database then that message attachment is extracted and placed into the new EDB.  So in short you may gain in one area and lose in others so that in the end mailbox size may end up being larger or smaller depending upon how much data was removed vs affected by SIS.
    3. That said James is correct in that the OLD message store will not change size when you move a mailbox out to another database UNLESS post move you defragment it
    4. He is also correct that your best move to avoid downtime would be to move all users to a new DB and then drop the old DB when done.  Actually I would take the old one offline for a day or two to ensure nothing was missed and then when you are comfortable delete the old DB.
    5. Also if you do this ensure that you modify you backup product to stop backing up the old DB and start protecting the new DB

    Troy Werelius
    www.Lucid8.com
    • Marked as answer by JasonBeckett Wednesday, March 23, 2011 12:26 AM
    Tuesday, March 22, 2011 11:24 PM