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Exchange Database Compacting

    Question

  • Morning all,

    We are running Exchange server 2003 SP2.

    We have 4 Storage Groups with 5 mailstores in each storage group (5 databases)

    We have just implemented a large email archiving platform which has reduced the amound of mail held within the exchange databases, creating a lot of whitespace.

    We now want to run eseutil to compact the databases and reclaim all the whitespace.

    I know how to run eseutil to do the compacting but now that we have 20 large (between 20 - 100gb) databases to compact, I have made recommendations to my management to do 1 database at a time over a period of weekends bearing in mind the time it can take to copy and compact the databases.  I am being asked the question is it possible to do more than one database at a time ?

    My answer was yes it could be done by copying them away and running eseutil locally to do the compaction, but I wouldn't recommend doing more than database in case of problems.

    What is the feeling here and what would be Microsofts recommendations for/against doing this ?

    Thanks

    Graham

    Friday, August 06, 2010 10:16 AM

Answers

  • I dont like the idea  :)

    There is always risk when you run eseutil against a store so backups before and after are key and the downtime IMO, is unacceptable.

     

    • Marked as answer by GT7822 Thursday, August 12, 2010 9:31 AM
    Friday, August 06, 2010 3:17 PM
  • You are aware it is total downtime while the work is being done?
    You cannot have any part of Exchange running, because the database files would change. That means all users.

    How large are the databases? Can you afford the downtime? The process goes along at between 1 and 4gb per hour, depending on the hardware, so if you have 40gb of white space you are already look at a worse case scenario of 40 hours, just for one database.

    Even with the constraints that you have outlined, I would still be wanting to move the mailboxes around. If you have large amounts of white space in the databases, then moving mailboxes about isn't going to use that much more space, because the white space will be used by those mailboxes that you have moved.

    Zero downtime, zero risk - which is NOT something that can be ever said about an offline defrag.

    Simon.


    Simon Butler, Exchange MVP. http://blog.sembee.co.uk , http://exbpa.com/
    • Marked as answer by GT7822 Thursday, August 12, 2010 9:31 AM
    Friday, August 06, 2010 4:30 PM

All replies

  • How much is a lot of whitespace?

    Can you simply move mailboxes to other stores, emptying the stores with the most whitespace to reclaim, then removing them or recreate them?

     

    Friday, August 06, 2010 10:54 AM
  • We have 5 mailstores in each of the storage groups (taking us to the max), we have approx 4000 users spread over all the stores.

    The whitespace varies for each mailstore but is between 10 and 40 gb.

    Moving mailboxes is not an option

    Thanks

    Friday, August 06, 2010 2:10 PM
  • Copying to other locations and running eseutil seems like a lot of work and too much down-time.

    Personally, I would not compact any - I prefer moving mailboxes, but if you decide to do this, I would only defrag those above 30GB maybe? Since the whitespace will be reclaimed by Exchange anyway, that space will be refilled at some point in the future.

    Friday, August 06, 2010 2:19 PM
  • I understand your reasoning but due to IT contingency restraints and needing to get the databases below 50% of actual disk space is a must.

    I know the databases will start to grow again once they have been compacted but we have an archiving solution in place that will create additional whitespace on a weekly basis, so the database should start to stabilize.

    I just want to know what your feeling are on doing more than one database at a time on different drives/servers.

    I personally don't like the idea but I need to explain to management why I don't like the idea, was just trying to get some feelings from here.

    Thanks

    Friday, August 06, 2010 2:39 PM
  • I dont like the idea  :)

    There is always risk when you run eseutil against a store so backups before and after are key and the downtime IMO, is unacceptable.

     

    • Marked as answer by GT7822 Thursday, August 12, 2010 9:31 AM
    Friday, August 06, 2010 3:17 PM
  • You are aware it is total downtime while the work is being done?
    You cannot have any part of Exchange running, because the database files would change. That means all users.

    How large are the databases? Can you afford the downtime? The process goes along at between 1 and 4gb per hour, depending on the hardware, so if you have 40gb of white space you are already look at a worse case scenario of 40 hours, just for one database.

    Even with the constraints that you have outlined, I would still be wanting to move the mailboxes around. If you have large amounts of white space in the databases, then moving mailboxes about isn't going to use that much more space, because the white space will be used by those mailboxes that you have moved.

    Zero downtime, zero risk - which is NOT something that can be ever said about an offline defrag.

    Simon.


    Simon Butler, Exchange MVP. http://blog.sembee.co.uk , http://exbpa.com/
    • Marked as answer by GT7822 Thursday, August 12, 2010 9:31 AM
    Friday, August 06, 2010 4:30 PM