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reclaiming white space RRS feed

  • Question

  • Hello,
    We have Exchange 2010 SP1 (update rollup 6 applied)

    I have a question about whitespace in Exchange DB. If I move a mailbox to another mailbox database, original DB does not shrink.
    Is there a way to reclaim that space?

    I have seen postings where following two options are mentioned:
    1) take DB offline and run emctl command
    2) create another mailbox DB and move mailboxes to the new DB.

    What other options are there besides these two?

    Is there a way to reclaim the white space with maintenance schedule?
    I saw this article about viewing DB defragmentation tasks by performance counters, but not sure how to access these? Is this accessed from EMC or EMS? http://technet.microsoft.com/en-us/library/bb691410.aspx


    Thanks!

    Saturday, April 28, 2012 7:49 PM

Answers

  • Your best bet is to create a new DB an move the mailboxes over to it. I believe I read an article saying that this is actually how Microsoft does it too...don't quote me on that though.

    You can't reclaim the space without an offline defrag or new database. With Exchange 2010, moving user mailboxes isn't a big deal because you can do it online. I would suggest moving ALL the users from the "whitespace" database to a new database (which will be much smaller), and then delete the old database. In my experience, it's the easiest and fastest way to get it done.

    Good Luck!

    -Dan


    Please click "Vote as Helpful" if this post was helpful to you. Thanks!

    • Proposed as answer by Mike Crowley Sunday, April 29, 2012 12:53 AM
    • Marked as answer by umsystems Monday, April 30, 2012 1:36 PM
    Saturday, April 28, 2012 8:06 PM
  • Exchange will reuse white space before start growing the size of the database. Let’s say your database is 10 GIG, and you have deleted 2 Gig worth mail data out from your DB.

    How big is your database now? The answer is 10GIG. If the size of the database did not change what happened to 2 GIG data we have deleted and purged out of the database, it become what is called “White Space” Now here is where the magic happens. You have added 1 GIG mail data on this database, what is the size of your database now?  The answer is still 10GIG. Exchange used white space and did not need to grow your Database size. As you can see, think your database as bucket which can hold 10GIG data, when you get rid of 5 Gig the bucket is still 10GIG, although half of it is empty and won’t get any bigger until it gets filled out, when it does the bucket will have to grow.

    If you need to check the white space

    Get-MailboxDatabase Database1 -Status | FL AvailableNewMailboxSpace

    good luck

    ocd


    Oz Casey, Dedeal MCITP (EMA), MCITP (EA), MCITP (SA) Visit smtp25.blogspot.com Visit Telnet25.wordpress.com   This posting is provided AS-IS with no warranties or guarantees and confers no rights.

    • Proposed as answer by Mike Crowley Sunday, April 29, 2012 12:53 AM
    • Marked as answer by wendy_liu Friday, May 4, 2012 7:02 AM
    Sunday, April 29, 2012 12:35 AM

All replies

  • Your best bet is to create a new DB an move the mailboxes over to it. I believe I read an article saying that this is actually how Microsoft does it too...don't quote me on that though.

    You can't reclaim the space without an offline defrag or new database. With Exchange 2010, moving user mailboxes isn't a big deal because you can do it online. I would suggest moving ALL the users from the "whitespace" database to a new database (which will be much smaller), and then delete the old database. In my experience, it's the easiest and fastest way to get it done.

    Good Luck!

    -Dan


    Please click "Vote as Helpful" if this post was helpful to you. Thanks!

    • Proposed as answer by Mike Crowley Sunday, April 29, 2012 12:53 AM
    • Marked as answer by umsystems Monday, April 30, 2012 1:36 PM
    Saturday, April 28, 2012 8:06 PM
  • Thank you for reply;

    I saw an article that Exchange 2010 can support upto 100 mailboxe DBs.
    Is there any performance issue if I run more than one DB on same partition (is this okay to do)?
    Our mailbox DBs are on SAN disks connected via FC.

    Thank you,

    Saturday, April 28, 2012 8:47 PM
  • Well you won't really be adding any additional load (users/clients) so I don't think performance would be affected. I would check how your backups are configured, there are a few small potential issues there. Also log growth, moving a lot of mailboxes generates a lot of logs! Be careful with that one. I've just never had good luck using eseutil, it's always been so slow. This way you can keep users online and get the space back.

    If you have other DB's, maybe you could split the users up between them, create the new DB and then move them back?


    Please click "Vote as Helpful" if this post was helpful to you. Thanks!

    Saturday, April 28, 2012 9:13 PM
  • Thank you again for the answer.

    Have another came to mind:

    Does the whitespace in DB ever gets used?
    I moved about 20GB to new DB few days ago, but running following command shows only 2GB for "AvailableNewMailboxSpace"

    Get-MailboxDatabase -Status | Select-Object Server,Name,AvailableNewMailboxSpace

    FYI: we use netbackup, and do a full GRT based backups every day, so logs get "cleaned up" daily...

    Thank you,

    Saturday, April 28, 2012 11:47 PM
  • From what I understand, you get whitespace after a DB grows and then content is purged (a mailbox is deleted). When the Online maintenance runs, that frees the space and makes it available to be used by the DB again, for other mailboxes or whatever. So every time the database grows larger, the min size of the edb file grows. The only way to shrink that file size is through Offline Maintenance or by moving the mailboxes to a new database and removing the old one.

    Before I confuse you though...you should read from the experts instead:

    http://blogs.technet.com/b/exchange/archive/2011/12/14/database-maintenance-in-exchange-2010.aspx

    I hope this helps. Please mark this as answered and helpful if it was. :)

    Thanks!

    -Dan


    Please click "Vote as Helpful" if this post was helpful to you. Thanks!

    Sunday, April 29, 2012 12:25 AM
  • Exchange will reuse white space before start growing the size of the database. Let’s say your database is 10 GIG, and you have deleted 2 Gig worth mail data out from your DB.

    How big is your database now? The answer is 10GIG. If the size of the database did not change what happened to 2 GIG data we have deleted and purged out of the database, it become what is called “White Space” Now here is where the magic happens. You have added 1 GIG mail data on this database, what is the size of your database now?  The answer is still 10GIG. Exchange used white space and did not need to grow your Database size. As you can see, think your database as bucket which can hold 10GIG data, when you get rid of 5 Gig the bucket is still 10GIG, although half of it is empty and won’t get any bigger until it gets filled out, when it does the bucket will have to grow.

    If you need to check the white space

    Get-MailboxDatabase Database1 -Status | FL AvailableNewMailboxSpace

    good luck

    ocd


    Oz Casey, Dedeal MCITP (EMA), MCITP (EA), MCITP (SA) Visit smtp25.blogspot.com Visit Telnet25.wordpress.com   This posting is provided AS-IS with no warranties or guarantees and confers no rights.

    • Proposed as answer by Mike Crowley Sunday, April 29, 2012 12:53 AM
    • Marked as answer by wendy_liu Friday, May 4, 2012 7:02 AM
    Sunday, April 29, 2012 12:35 AM
  • Thank you Dan for your time and answers!

    Monday, April 30, 2012 1:37 PM
  • Oz,
    Thank you for your explaination. That is what I read also, but not what is happening in our Exchange environment (Exchange 2010 Ent. SP1 UR6).
    I also saw couple of blogs that mentioned that the "white space" does not get used until "keep deleted items" setting? So, it hasn't been very clear.

    I am not running out of space, but Exchange backups are getting longer...

    Thanks again,

    Monday, April 30, 2012 1:43 PM
  • Hi

    White space will only become available once the database retention period of the deleted items or disabled mailboxes passes.

    Cheers, Steve

    Monday, April 30, 2012 1:48 PM
  • In Exchange 2010,I recommend you to move all the mailboxes in the database to other database and recreate the database file to claim the space.One of the advantage of moving mailboxes when compared to other version of exchange.In exchange 2010,it is build on dumpster 2.0.The speciality of dumpster 2.0 it will move the recovery deleted items also while moving the mailboxes.But in exchange 2003 and exchange 2007 is build on dumpster 1.0 where recovery deleted items are lost when moving the mailbox.

    In a DAG environment,doing offline defrag is not good idea.Because we need reseed the database again to passive copy.The best is to move the mailbox to other database.While moving the mailbox enable circular logging.



    Siddiq Growth and Comfort do not coexist

    • Proposed as answer by abuexchange Monday, April 30, 2012 3:03 PM
    Monday, April 30, 2012 1:56 PM
  • Your best bet is to create a new DB an move the mailboxes over to it. I believe I read an article saying that this is actually how Microsoft does it too...don't quote me on that though.

    You can't reclaim the space without an offline defrag or new database. With Exchange 2010, moving user mailboxes isn't a big deal because you can do it online. I would suggest moving ALL the users from the "whitespace" database to a new database (which will be much smaller), and then delete the old database. In my experience, it's the easiest and fastest way to get it done.

    Good Luck!

    -Dan


    Please click "Vote as Helpful" if this post was helpful to you. Thanks!

    Hi Dan,

    I'm in little pickle. We have database with mailbox that grew up to 170GB and the whole database to 340GB. Now I have removed 168GB of data (size of whitespace) and I was asked to reclaim whitespace.

    - Offline defrag will need lots of space and will take ages so it is not even considered.

    - Creating new database and moving mailboxes. I am not sure when whitespace is cleaned. It looks that I would need at least 174GB disk space to move mailboxes before there is 168GB released from whitespace. Or is the whitespace released on the go from deleted mailbox (that has been moved to new database)? We have about 75GB free on the drive so it looks that the only option is to wait for the database to reuse whitespace.

    Can you give me advise on this?

    Thanks
    Krzysztof

    Friday, April 22, 2016 10:04 AM
  •  ok so

    1. White space is never cleaned up i.e. the physical size of the EDB never changes UNLESS you do an offline defragmentation. 

    2. Instead as white space is freed up new data can technically use that space IF its been released after the deleted item/mailbox retention settings are reached. 

    3. So yes you can move the mailboxes into a new database and once all the mailboxes have been moved out of the existing DB you can delete that DB from the server or dial tone it.

    Now the problem you have appears to be that you don't have enough disk space to move all the users from the existing DB into a new DB.

    So with that said your choices are

    A: add more disk space and do the move mailbox process and then delete the existing DB

    B: Leave things as they are and reuse the white space for new data

    C: the other option would be to down the DB, copy it off to an alternate location, confirm it can be opened by a third party tool like Lucid8'd DigiScope.  Then dial tone the DB which in short will make a new blank DB for the users and email will begin to flow again, however the historical email will not be present.  Then use DigiScope to restore the historical data to the new dial toned DB


    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 --> 2016 with Lucid8's DigiScope http://www.lucid8.com/product/digiscope.asp


    Friday, April 22, 2016 7:24 PM
  • Note that Exchange 2010 Standard edition has a maximum of 10 mailbox databases!
    Monday, September 30, 2019 7:10 AM