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Offline Defrag? Worthwhile?

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  • Offline Defrag? Worthwhile?

    This is a bit of an open question because I'm trying to get a feel for what has worked for other Exchange Admins.

    I'm looking to put together a more solid maintenance schedule for our Exchange cluster and I've been looking for advice on doing offline defrags.

    I know there are specific situations when an offline defrag can bery helpful.

    -Moving large groups of users
    -Keeping database under the size limits
    -Running out of space on the volume

    Aside from that, is there any reason or benefit to doing offline defrags as part of a regular maintenance schedule? Not weekly or even monthly, I was thinking quarterly or even every 6 months+.

    Specifically, we run 2003 Enterprise in a clustered environment.
    CCA: XenApp 5.0

  • #2
    Re: Offline Defrag? Worthwhile?

    First thing I would suggest is that you read this blog posting from the MS Exchange Team:

    In short, offline defrag should NOT be considered something that needs to be done on a regular basis. Most Exchange servers do not need any kind of maintenance - they are best left alone. As long as you back them up regularly then that is almost all they need. Obviously maintain patches, updates and service packs, but that is the same for any application.

    I don't do offline defrags except for the following reasons

    - I hit the 16gb (pre E2003) or 75gb limit (E2003) (doesn't apply to you as you will be on Enterprise)
    - I will gain at least 40% of the space back AND I will not be using that again (for example a lot of staff have been fired or an archiving application has been deployed)
    - I am directed to by Microsoft Support.

    Even so, if I was going to gain the space, there are a lot more efficient ways of getting the space back that do not involve downtime. Additional databases and moving mailboxes around for example.

    Then you have to take in to account the downtime. It is TOTAL downtime, as Exchange cannot be running at all. The process works at between 1 and 4gb per hour, depending on hardware, so you will have to work out how long you would be down.

    Simon Butler
    Exchange MVP

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    • #3
      Re: Offline Defrag? Worthwhile?

      Thanks for the reply Sembee.

      Your response and the link is the general impression I got when I was searching on this topic.

      I was worried that eventually the database would become sluggish and an offline defrag would be necessary to reclaim not only disk space but lost performance.

      We also have an P series AIX machine running DB2 that we REORG 4-5 times a month. This machine runs a financial database. Without regular REORGs performance starts to degrade. I'm thinking the offline defrag and the DB2 REORG are not as similar as I originally thought .
      CCA: XenApp 5.0