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Defrag Exchange information store RRS feed

  • Question

  • I have Exchange 2003 with two information stores.  The PRIV.EDB for the first store is roughly 60GB while the PRIV.EDB for the second store is about 6GB. 

    Obviously when I defrag the databases, I will need to do this twice, once for each EDB file. 

    I want to split some of the users across as evenly as possibe before defragging anything.  If I move some users from the first store to the second store and I defrag the first store, will it regain that empty space back? 

    What is the best way to go about offline defragging two exchange information stores with minimal impact and less time?

     
    Monday, July 2, 2012 3:45 PM

Answers

  • The White Space will be regained when you move mailbox from First Store to Second Store or Vice Versa.

    ---

    If you have good space . Move Everyone to the Second Store and Mount a Blank Store.

    And Move them Back to First Store.

    --

    Minimal Impact - IF you have less space on your drives , There is no other go , than Dismounting your stores to do a offline defrag


    Satheshwaran Manoharan | Exchange 2003/2007/2010 | Blog:http://www.careexchange.in | Please mark it as an answer if it really helps you

    • Proposed as answer by Terence Yu Tuesday, July 3, 2012 5:33 AM
    • Marked as answer by Banc0 Thursday, July 5, 2012 6:36 PM
    Monday, July 2, 2012 3:52 PM
    1. Short answer yes if you move some from the 1st to the 2nd and then defrag the store you will regain space as long as the mailbox deleted item retention has passed. 
    2. However that said if you are attempting to regain space from the databases the better move would be to create a 3rd store, move users from the 1st to the 2nd and 3rd and then you can delete or better yet dial tone the 1st store so that its small again and then can be used to move mailboxes from the other stores in the future.

    NOTE: Unless you have over 10% of the DB size in white space then its really not worthwhile to do a defrag since the DB will reuse the space over time.


    Troy Werelius
    www.Lucid8.com
    Search, Recover, & Extract Mailboxes, Folders, & Email Items from Offline EDB's and Live Exchange Servers with Lucid8's DigiScope

    • Proposed as answer by Terence Yu Tuesday, July 3, 2012 5:33 AM
    • Marked as answer by Banc0 Thursday, July 5, 2012 6:36 PM
    Monday, July 2, 2012 3:53 PM

All replies

  • The White Space will be regained when you move mailbox from First Store to Second Store or Vice Versa.

    ---

    If you have good space . Move Everyone to the Second Store and Mount a Blank Store.

    And Move them Back to First Store.

    --

    Minimal Impact - IF you have less space on your drives , There is no other go , than Dismounting your stores to do a offline defrag


    Satheshwaran Manoharan | Exchange 2003/2007/2010 | Blog:http://www.careexchange.in | Please mark it as an answer if it really helps you

    • Proposed as answer by Terence Yu Tuesday, July 3, 2012 5:33 AM
    • Marked as answer by Banc0 Thursday, July 5, 2012 6:36 PM
    Monday, July 2, 2012 3:52 PM
    1. Short answer yes if you move some from the 1st to the 2nd and then defrag the store you will regain space as long as the mailbox deleted item retention has passed. 
    2. However that said if you are attempting to regain space from the databases the better move would be to create a 3rd store, move users from the 1st to the 2nd and 3rd and then you can delete or better yet dial tone the 1st store so that its small again and then can be used to move mailboxes from the other stores in the future.

    NOTE: Unless you have over 10% of the DB size in white space then its really not worthwhile to do a defrag since the DB will reuse the space over time.


    Troy Werelius
    www.Lucid8.com
    Search, Recover, & Extract Mailboxes, Folders, & Email Items from Offline EDB's and Live Exchange Servers with Lucid8's DigiScope

    • Proposed as answer by Terence Yu Tuesday, July 3, 2012 5:33 AM
    • Marked as answer by Banc0 Thursday, July 5, 2012 6:36 PM
    Monday, July 2, 2012 3:53 PM
  • I have over 122GB of free space on the drive where Exchange sits.  I can definitely create a third store but I don't know if I want to move everybody into a third store and back again.  I'll have to see...

    More importantly though, will splitting the users and defragging the stores solve any performance issues?  Part of the reason why I am looking to do this is because of the numerous complaints of how slow a user's inbox is especially when they try to search or sort mail.  Would this help?

    Also can I dismount one store and defrag it while leaving the other store up and running so that some people can still reach outlook? 

    • Edited by Banc0 Monday, July 2, 2012 4:28 PM
    Monday, July 2, 2012 4:25 PM
    1. Yes the downside to moving mailboxes is that while that mailbox is being moved it cannot be accessed however its better in that it only effects that user vs all users within the store
    2. As far as speed is concerned that's a tough issue because it could be multiple issues, i.e.

    A: The users workstation, network connection etc. 

    B: The users mailbox in that if they have a very large mailbox and they are keeping  a large # of items in the root inbox or other folder they are accessing then its going to take more time to accessing just like it would if you put 100K items in a folder on disk it takes longer to enumerate them than if it was a smaller # so could be a case of mailbox management would help resolve the issue

    C: Another users mailbox is impacting all other mailboxes.  So like item B above if you have a pack rat power user that has an enormous # of folders and items it can certainly impact the other users.

    So based upon the above I would recommend that you first look at the users machine i.e.

    A: Are they in cached mode?  if not try turning caching on and see if that makes a difference, if they are already in cached mode then you might look at the size of the OST to see if its reaching its limit and if so you may need to archive some of the users items.  You can also turn caching off to see if that makes a difference and if so try rebuilding the OST file, i.e. delete the old, turn caching on and let it build

    B: Check to ensure the paging file is set to the proper size i.e. 1.5 x memory since excessive paging could be an issue as well

    C: Ensure the users network connection is not an issue

    D: Have you tried having the user access their mailbox via another machine to see if its a machine vs mailbox issue?

    E: If its just one user it could be that moving that user to another database and maybe even just putting them on their own database to start with could help but it doesn't necessarily resolve the root issue


    Troy Werelius
    www.Lucid8.com
    Search, Recover, & Extract Mailboxes, Folders, & Email Items from Offline EDB's and Live Exchange Servers with Lucid8's DigiScope

    Monday, July 2, 2012 4:39 PM
  • we always have users with lots of folders.  The user complaining is currently 1 of 2 users on a separate exchange information store. 

    Not sure where the lag is, but again, it occurs during things like searching, etc.  Generally it's also good practice to offline defrag every once in a while.  It does speed things up.  Just that it hasn't been done in a while and the user count is growing day by day.

    User is definitely in cached mode and the mailbox is not that large (under 1GB)

    Monday, July 2, 2012 9:11 PM
  • What do you mean the user count is growing day by day, i.e. are you adding more users to the system constantly or ??

    Have you looked at whats happening on the Exchange server and the users box at the time the issue is taking place, i.e. could be that something is going on within the users machine the Exchange server or the network during the times of concern


    Troy Werelius
    www.Lucid8.com
    Search, Recover, & Extract Mailboxes, Folders, & Email Items from Offline EDB's and Live Exchange Servers with Lucid8's DigiScope

    Monday, July 2, 2012 10:31 PM
  • Not constantly but every few weeks a new user could be starting. 

    Another strange thing I noticed, one user was moved to a new storage group.  He cleaned out about 13000 messages and I still don't see a drop in mailbox size when I check it in ESM.  Very odd.  The retention period is set for 1 day but at the time it was set for 14 days. 

    Perhaps there is a cleanup agent that also needs to be run?

    Tuesday, July 3, 2012 12:20 PM
  • Well the new time should be the ruling factor but that is assuming that A: your nightly maintenance has been completing and good article here http://blogs.msdn.com/b/jeremyk/archive/2004/06/12/154283.aspx(overlap with backup windows can truncate this) and that B: a full backup has taken place since that time since the default is Exchange IS configured to require a full backup before permanently deleting items.

    Troy Werelius
    www.Lucid8.com
    Search, Recover, & Extract Mailboxes, Folders, & Email Items from Offline EDB's and Live Exchange Servers with Lucid8's DigiScope

    Tuesday, July 3, 2012 1:30 PM
  • Few more questions:

    1) Would moving a user mailbox to a new (or another existing) storage group essentially "compact" it?  In other words, would it only copy the things that need to be copied, eliminating whitespace?  Basically means I don't even need to defrag the information store just by the simple act of moving a mailbox?

    2) Is it better to create several smaller storage groups (approximately 15-20GB) each and populate them with a handful of users?  Thereby creating small, more digestable, groups to manage and administer?  That means smaller defrag time, less hassle to everyone since you are only affecting a small group of users, etc?

    Thursday, July 5, 2012 6:00 PM
  • 1) Essentially, no.  The white space is left behind in the database after you move the mailbox out, it is roughly equal to the size of the mailbox once it has been moved.  The only way to reclaim this space is a offline defrag.

    2) This depends on your environment but I would think that storage groups that small might present their own problems.

    Thursday, July 5, 2012 6:31 PM
  • 1) Right but what about the DESTINATION storage group?  Wouldn't moving mailboxes to another storage group keep things trim? 

    2) What sort of problems might arise from maintain several smaller information stores?

    Thursday, July 5, 2012 6:34 PM
  • No becuase

    1. Because the white space is int database itself 
    2. Pre 2010 there is a feature called single instance storage that in short when an attachment is sent IF there is more than 1 recipient and IF those recipients are in the same store then there will only be one copy of an attachment for all recipients that are in that database.  So when you move that mailbox could very well take up more space on the new DB and then the space from the old mailbox turns into DB white space post retention

    Troy Werelius
    www.Lucid8.com
    Search, Recover, & Extract Mailboxes, Folders, & Email Items from Offline EDB's and Live Exchange Servers with Lucid8's DigiScope

    Thursday, July 5, 2012 6:37 PM
  • 1) Yes, anything that is written to the database will normally start to use up the white space before increasing the size of the EDB file. 

    2) Mainly around mailbox management.  You might find yourself spending a lot of time moving mailboxes around to keep the sizes down.

    Thursday, July 5, 2012 6:40 PM