Exch 2007 database size doesn't match up with sum of mailbox sizes

The exchange database (.edb) is showing as approx 30GB in Windows Explorer.  When I run a "get size" script, the total of the mailbox sizes is only 15 or so GB. So, I'm wondering what the other 14 GB is being used by, or what it is for?   Does this mean I need to run a db defrag or other utility?
StewartTechnologiesIT ConsultantAsked:
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Seth SimmonsSr. Systems AdministratorCommented:
look in your application log for event id 1221
the difference in size could be white space
you could run a defrag on the database to release the disk space though a better approach would be to create a new database and move mailboxes
Amit KumarCommented:
There will be a whitespace in EDB file that's why you are able see mailbox size upto 15 GB only.

To discover how much free space is available in your database files, look for an Event 1221 in the Windows application event log. There will be separate events logged for each database after online defragmentation completes for that database. The event descriptions will be similar to the following:

The database has 151 megabytes of free space after online defragmentation has terminated.

If you don't have any space crunch on your hardware so no need to defrag edb file as I hope you have configured Online defrag/maintenance on your DB. You can check by opening DB properties it will scheduled for a particular time. Still if you want to defrag your database file it will have downtime as it will be a offline defrag by ESEUtil:

C:\program files\microsoft\exchange server\bin Eseutil /d c:\program files\exchange server\mailbox\<storage_group_name>\<database_name>.edb

I won't prefer offline defrag as it will be a downtime, but still if you want to run it so please be careful. Before defraging  database take a full backup and also take separate copy of DB file and Log files.

There is one another way to defrag your DB, create another database and move all users in new DB, you will have actual size of DB after complete movement of users.

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StewartTechnologiesIT ConsultantAuthor Commented:
Thanks for the feedback so far.  

I'm concerned about making a new Exch db as this is Exch 2007 on SBS 2008, and SBS does some very unique items to Exchange and I'm concerned in the long run, this new DB will cause more issues.  
Any ideas on this?
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StewartTechnologiesIT ConsultantAuthor Commented:
Just as an update, db is 36 GB.  That seems like excessive white space.  We are having performance issues (sluggishness and freezing), which is why I'm considering eseutil or a new DB (under the same storage group).
StewartTechnologiesIT ConsultantAuthor Commented:
Following the event log suggestion, I have found this log ...

"First Storage Group\Mailbox Database" has 13530 megabytes of free space after online defragmentation has terminated. "   

This is 13 some Gigs right here.  How can I purge this large swath of free space?

Thank you.
Amit KumarCommented:
There is a way to offline defregment but as you mentioned you are facing some performance issues so better to create a new DB and move all users to new DB.

Else you can do offline defrag. Reference Article for ESEUtil Defragment details.

Command: C:\program files\exchsrvr\bin> Eseutil /d c:\progra~1\exchsrvr\mdbdata\priv1.edb

Note: Offline Defag process is time taking process and it need downtime of Database.
StewartTechnologiesIT ConsultantAuthor Commented:
Thank you both for your help.  I ended up creating a new DB and moving all the mailboxes. We are now at a more appropriate db size.
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