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Offline Defragmentation of Exchange Database 2010 RRS feed

  • General discussion

  • Dear All,

    I am having a doubt. Please let me know whether OFFLINE DE-FRAGMENTATION of an EDB file is recommended by Microsoft or NOT?

    After performing eseutil /d, would there be any DATALOSS?

    Please let me know the proper and exact information.

    Thanks in advance.


    Regards, Jay.

    Wednesday, July 16, 2014 6:00 AM

All replies

  • Hello,

    Offline defragmentation is not recommended and normally not needed. Offline defrag should be used only in special cases, i.e. when running out of disk space. This operation normally doesn't cause any data loss but you can take backup to make sure that you can rollback unsuccessful defrag.

    In normal day-to-day scenarios online maintenance is sufficient: http://blogs.technet.com/b/exchange/archive/2011/12/14/database-maintenance-in-exchange-2010.aspx.

    Wednesday, July 16, 2014 6:36 AM
  • The recommended approach is to create a new mailbox database and move the mailboxes to it.
    Wednesday, July 16, 2014 6:41 AM
  • The defrag /D will not cause any data loss, however as the others stated;

    1. This is not a recommended path by MS and should only be taken under certain conditions

    2. The best path as Steve said is to create a new fresh Database and then move the mailboxes from Existing DB to new DB.   Once completed you can either remove the old DB or just dial tone it i.e. dismount the old DB, then remove the DB and log files from disk, then go back and mount in EMC and it will create a new BLANK DB that you can leave in place for future MB moves back into it.


    Search, Recover, & Extract Mailboxes, Folders, & Email Items from Offline Exchange Mailbox and Public Folder EDB's and Live Exchange Servers or Import/Migrate direct from Offline EDB to Any Production Exchange Server, even cross version i.e. 2003 --> 2007 --> 2010 --> 2013 with Lucid8's DigiScope

    Wednesday, July 16, 2014 1:31 PM
  • Why are you trying to defrag the database? Are you wanting to reclaim the whitespace. Whatever the reason it is not recommended for the offline defrag. This can take a very long time. The best way is to create a new database and move users to it and then delete the old database. Be sure you check for the system mailbox before you delete the old database and make sure you have space for the new database as it will take the users data from the old database.

    Get-MailboxDatabase -status | fl Name, Databasesize, AvailableNewMailboxSpace

    Get-Mailbox -Arbitration | Where {$_.Name -like "SystemMailbox*"} | ft -wrap


    HossFly, Exchange Administrator

    Wednesday, July 16, 2014 3:33 PM