locked
Online Defragment RRS feed

  • Question

  • Hi,

    I run Exchange 2007. The Exchange database is on 100 GB disk partition. Recently I noticed the free space for this partition is getting small, around 10 GB. I arranged to have user to archive their mailboxes, delete unwanted emails. I know the free space won't show up until I do database defragment. But before I do so, the free space suddenly increased to 17 GB. I checked the log file and found online defragment is completed. but it seems the online defragment has been going everyday. My questions are:

    • Why the free space suddenly increase although the online defragment is doing everyday?
    • Do I still need to manually run offline defragment using Eseutil?

    Thanks in advance!


    Grace

    Wednesday, July 4, 2012 12:28 AM

Answers

    • Why the free space suddenly increase although the online defragment is doing everyday?

    Yes, Online defrag process will only create white space and does not increase any free space. While checking your free disk space you must also consider the Catalog folder size. This catalog folder is created if you have indexing enabled for the database. I have seen this situation within my own mailbox server where the catalog folder will shrink the catalog size after it reaches a threshold. When checked with MS, i was told that this threshold is coded and cannot be changed.

    I believe the sudden increase in your free space is due to this catalog shrink. If so, an event 4165 will be logged under MSFTESQL Service category. The shrink process is termed as master merge in the event.

    • Marked as answer by emma.yoyo Wednesday, July 11, 2012 1:48 AM
    Wednesday, July 4, 2012 6:05 AM

All replies

    1. The online defragmentation process by default runs everyday between 1-5AM but you can adjust it as needed and more about that here http://technet.microsoft.com/en-us/library/bb629590%28v=exchg.80%29.aspx
    2. When the nightly maintenance runs it checks items that have been deleted to see if they are within the deleted item retention setting. More about that here http://technet.microsoft.com/en-us/library/bb125266%28v=exchg.80%29.aspx and any items that have reached or gone beyond the settings are freed up in the database so that other items can use the space.
    3. Now its important to understand this just frees the space internally, i.e. it will NEVER shrink the physical database, for that you need to run eseutil /d however your DB should not grow at this point unless you are adding items faster than the white space is being freed up.
    4. Another thing to check however is the # of logs you have on your system, i.e. your nightly backup should truncate them so if that is not happening then you should address the backup issue ASAP.

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

    Wednesday, July 4, 2012 2:36 AM
  • On Wed, 4 Jul 2012 00:28:34 +0000, graceyin39 wrote:
     
    >I run Exchange 2007. The Exchange database is on 100 GB disk partition. Recently I noticed the free space for this partition is getting small, around 10 GB. I arranged to have user to archive their mailboxes, delete unwanted emails. I know the free space won't show up until I do database defragment. But before I do so, the free space suddenly increased to 17 GB. I checked the log file and found online defragment is completed. but it seems the online defragment has been going everyday. My questions are: Why the free space suddenly increase although the online defragment is doing everyday?Do I still need to manually run offline defragment using Eseutil?
     
    If your online maintenance schedule is set to run continuously
    (probably not a good idea) and your deleted item retention time is set
    to zero and you haven't configured the database to keep deleted items
    until a full backup has been completed, then the deleted items are
    returned as free space immediately.
     
    Running eseutil requires that the database is dismounted. You don't
    want to do that. As long as you have sufficient free space within the
    database you database won't grow. But if you run eseutil to shrink the
    size of the database by removing all the free space then the database
    will begin to grow as soon as you remont it.
     
    ---
    Rich Matheisen
    MCSE+I, Exchange MVP
     

    --- Rich Matheisen MCSE+I, Exchange MVP
    Wednesday, July 4, 2012 3:44 AM
    • Why the free space suddenly increase although the online defragment is doing everyday?

    Yes, Online defrag process will only create white space and does not increase any free space. While checking your free disk space you must also consider the Catalog folder size. This catalog folder is created if you have indexing enabled for the database. I have seen this situation within my own mailbox server where the catalog folder will shrink the catalog size after it reaches a threshold. When checked with MS, i was told that this threshold is coded and cannot be changed.

    I believe the sudden increase in your free space is due to this catalog shrink. If so, an event 4165 will be logged under MSFTESQL Service category. The shrink process is termed as master merge in the event.

    • Marked as answer by emma.yoyo Wednesday, July 11, 2012 1:48 AM
    Wednesday, July 4, 2012 6:05 AM
  • Agree with Rajitha.

    Grace, suggest you also record the size of database file(.edb) at next time when you do something.


    Frank Wang

    TechNet Community Support

    Thursday, July 5, 2012 7:34 AM