Understanding Exchange database White Space

Posted on 2013-11-07
Medium Priority
Last Modified: 2013-11-08
ServerName                              Name                                    AvailableNewMailboxSpace
----------                              ----                                    ------------------------
ExchangeMB1                           MBdatabase8                                   114.2 GB (122,595,180,544 bytes)

Get-MailboxDatabase -identity MBdatabase8 -Status | select ServerName,Name,DatabaseSize

ServerName                              Name                                                DatabaseSize
----------                              ----                                    ------------
ExchangeMB1                           MBdatabase8                                   114.3 GB (122,684,506,112 bytes)

Get-MailboxStatistics -database MBdatabase8 | ft displayname,Totalitemsize,itemcount,storagelimitstat

DisplayName                   TotalItemSize                             ItemCount           StorageLimitStatus
-----------                   -------------                                     ---------            ------------------
John Smith                 31.39 MB (32,918,387 bytes)             373                    NoChecking
SystemMailbox{e06250a3-aa0... 318 B (318 bytes)                1                    NoChecking
Question by:jskfan
  • 3

Author Comment

ID: 39631787
in the display posted above, you can notice that :
Database size =114.3 GB (122,684,506,112
White space in the database=114.2 GB (122,595,180,544
The only mailbox in the database is about =31.39 MB (32,918,387 bytes)    

I do not understand how did the white space got there? I am not sure if there were mailboxes residing in that database then got moved...
how would an Exchange 2010 Expert explain that ?

Thank you
LVL 39

Accepted Solution

Hypercat (Deb) earned 1000 total points
ID: 39631835
Something was in that database that was later deleted. It could be deletions of items from that one mailbox (doubtful since it would have been one heckuva large mailbox), or it could be other mailboxes that were moved or purged from the database. Please take a look at this article.  Note that it states that the AvailableNewMailboxSpace is not a valid measure of white space in the database:


Also note that the recommended procedure for reclaiming that white space for use (other than by allowing the Exchange maintanence process to do it for you) is to create a new database, move the mailboxes to that database and then delete the old database.
LVL 22

Assisted Solution

by:Nick Rhode
Nick Rhode earned 1000 total points
ID: 39631950
It will remain that size and will not grow larger until that whitespace is filled.  There are 2 ways to handle the database and the best way is to create a new mailbox database and move the mailboxes as stated by hypercat or use the ESEUtil (which I don't recommend) but it will defrag the database.

I am assuming mailboxes were purged or moved from the database in some form.


Author Closing Comment

ID: 39634033

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