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Exchange 2010 - Big discrepancy between database sizes and sum of all mailbox sizes RRS feed

  • Question

  • I realize there are a number of reasons why the reported database sizes will be larger than the sum of all mailboxes in our databases (whitespace, content indexing, dumpster, etc.), but out of over 1000 mailboxes I see only roughly 180GB of data used by the mailboxes between both of our databases (we have 2 databases both with passive copies in a DAG).  However, the size of each database (using "get-mailboxdatabase -status | fl DatabaseSize") is roughly 290GB for each database.  That means there is a 400GB discrepancy.  It also means that between the active and passive copies of the databases (basically 4 databases in total) we're using over 1.5TB of disk space.  Our database growth has started to level off since we migrated from Exchange 2003, and we archive our mailboxes nightly using Enterprise Vault based on age and quota.

    My boss has asked me to find out exactly what all of that space is being used for, and why.  The only method I have found to do this is by using "eseutil /MS "path to DB" > report.txt".  My problem is that I can't take the passive copy of either of the databases in the DAG offline to run that command, and I'm told the database has to be offline to run it.

    Is there another, perhaps better, method to retrieve a report to show how the data is being allocated?  Also, I'm trying to determine if this much of a discrepancy is normal in an environment of our size (about 1000 users).  I have found a lot of other forum posts similar to this but unfortunately none of them have a definative answer, and the discrepancies they list are much smaller than what I'm seeing.

    Thanks.

    Tuesday, January 10, 2012 3:58 PM

Answers

All replies

  • How much white space is being reported per database instance during maintenance?

    How are you computing the per mailbox size? Something like this?

    Get-mailboxstatistics | Sort-Object TotalItemSize –Descending | ft DisplayName,@{label=”Total Size (MB)”;expression={$_.TotalItemSize.Value.ToMB()}

    Tuesday, January 10, 2012 4:30 PM
  • Please Do check for maintanence Event ID 1221

    That should answer it .

    Please make sure your maintanence is running on your database properties

    Tuesday, January 10, 2012 4:37 PM
  • Hi,

    please check the retention time (both per mail and per deleted mailbox) configuren on the Mailbox Database. This is normally the reason why there is a diffrent between the size of the .edb file and the summation of all mailboxes.

    If order to shrink the size of the .edb file you have to execute an offline defragmentation of the database.

     

    More information about defragmentation you will find here:

    Exchange 2000/2003 http://support.microsoft.com/kb/328804/en-us

    Exchange 2010 http://technet.microsoft.com/en-us/library/dd351100.aspx

     

     


    regards Thomas Paetzold visit my blog on: http://sus42.wordpress.com
    Tuesday, January 10, 2012 4:59 PM
  • Our deletion settings are 15 days for deleted items and 30 days for deleted mailboxes.  I also use retention policies to purge everyone's Deleted Items, Junk E-Mail and Sync Issues folder of anything older than 15 days and allow recovery of deleted items for all 3 folder for another 15 days before it is permanently deleted.
    Tuesday, January 10, 2012 5:14 PM
  • How much white space is being reported per database instance during maintenance?

    How are you computing the per mailbox size? Something like this?

    Get-mailboxstatistics | Sort-Object TotalItemSize –Descending | ft DisplayName,@{label=”Total Size (MB)”;expression={$_.TotalItemSize.Value.ToMB()}

    Yes, something very similar to that.  Effectively the same thing, but I also include total items and a few other columns.
    Tuesday, January 10, 2012 5:16 PM
  • Please Do check for maintanence Event ID 1221

    That should answer it .

    Please make sure your maintanence is running on your database properties

    This is Exchange 2010 so no more Event ID 1221.  However, "get-mailboxdatabase -status | select availablenewmailboxspace" tells me I have about 35GB per database.
    Tuesday, January 10, 2012 5:17 PM
  • Hi,
    If you archive the mails with Enterprice Vault, I think you will find both the below links interesting.

    Same Issue: http://social.technet.microsoft.com/Forums/da-DK/exchange2010/thread/1e323602-2e8e-4261-b55c-a3bedd567b5b

    An Exchange Server 2010 database store grows unexpectedly large
    http://support.microsoft.com/kb/2621266

     


    Martina Miskovic - http://www.nic2012.com/
    Tuesday, January 10, 2012 5:42 PM
  • Ok, there's a script by Nuno Mota that I htink might be helpful in getting the 'true' mailbox size. http://social.technet.microsoft.com/Forums/en-US/exchangesvradmin/thread/130aafd5-b834-407a-a712-94f6dd815d98

    I guess change the -gt "400" to 0 and see if that gives you counts of both current mailbox and deleted items.  

    Tuesday, January 10, 2012 6:15 PM
  • Hi,
    If you archive the mails with Enterprice Vault, I think you will find both the below links interesting.

    Same Issue: http://social.technet.microsoft.com/Forums/da-DK/exchange2010/thread/1e323602-2e8e-4261-b55c-a3bedd567b5b

    An Exchange Server 2010 database store grows unexpectedly large
    http://support.microsoft.com/kb/2621266

     


    Martina Miskovic - http://www.nic2012.com/
    Yeah, this looks like it might be it.  I'm contact MS to get a copy of the hotfix first thing tomorrow and I'll post the results once I know.  We haven't installed Exchange SP2 yet so it may be a prerequisite for the hotfix.
    Tuesday, January 10, 2012 10:21 PM
  • Hi Matt

    Any update on this problem?

    Cheers

    Zi Feng

    Thursday, January 12, 2012 3:35 AM
    Moderator
  • I had to open a case in order to get hotfix 2621266. I applied it on Friday and was told it would be 1 or 2 weeks before I would see a difference. We have about 200% white space in our databases and the engineer I was working with remarked that he had not seen this much before on previous cases. More than likely I will have to create 2 new databases and move the mailboxes over to them so I can reclaim all of the space. Otherwise the only option is to do an offline defrag, which for us is unacceptable. I'll post back once I have more to report. Until I see solid results I'm not sure this is in fact the cause.
    Tuesday, January 17, 2012 10:05 PM
  • The hotfix addressed our issue.  The databases are now reclaiming white space properly instead of ignoring the white space and growing when they need room.  Our problem now is that we have a ton of white space in each database and in order to reclaim the space we need to create new databases and move the mailboxes since an offline defrag would take too long.
    Tuesday, February 21, 2012 2:51 PM