How to Reduce size of exchange server 2013 DB


I deleted some of users from Exchange server 2013 and still found the size of DB as the same.

How to clear the DB and free some space.
Abdulrhman AlamoudiAsked:
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Database files do not shrink when you delete users. The deleted space will be flagged as empty and Exchange is using this space until all "whitespace" is filled with data. Then it will increase the file size. Shrinking a database file is only possible during offline defragmentation. This process could need LOTS of time and during that time the database is offline (user Impact). Second, this process is dangerous and could lead to data loss.

Abdulrhman AlamoudiAuthor Commented:
Thankx Marcel_D

So did you prefer to move user-mailboxes to another a "New DB" and once move completed deleted the old one ?
That would be a possible solution if you are unable to extend storage/SAN/LUN.
The 7 Worst Nightmares of a Sysadmin

Fear not! To defend your business’ IT systems we’re going to shine a light on the seven most sinister terrors that haunt sysadmins. That way you can be sure there’s nothing in your stack waiting to go bump in the night.

offline defragmentation is recommended only if you don't have additional drive space to create new DB
If you do, then move mailboxes from old db to new, while moving, data will be moved sequentially and all white space would be covered and this process did not require any downtime
Derek SouterITO Svc Delivery Cons IIICommented:
depending on the version of Exchange you are using (Standard), and the number of databases you currently have - you may not have the option to create a new database and move the users (NB - if you move a user while they are using Outlook, they will receive a message stating that the administrator has made a change that requires them to close and re-open outlook).  

If you move all your users, then both databases must remain online until all users have re-opened outlook (otherwise Outlook will be unable to find their mailbox, and will require a new profile be created - expect lots of support calls).    

Offline defrag requires as much free space as the current size of the database - this can be on any drive, you specify the temp location as a parameter when starting an offline defrag

An offline defrag creates a temporary database where it puts all the information while it works on it - it then deletes the original and renames the temp DB at the end of the process (this is the only stage where data loss is likely)
MASEE Solution Guide - Technical Dept HeadCommented:
Here is a command to move from one database to another in bulk.
Get-Mailbox -Resultsize Unlimited -Database <OldDatabase> | New-MoveRequest -TargetDatabase <NewDatabase> -BatchName "<GiveABatchName>"

Open in new window

Note: As commented by Mahesh it is recommended only if you have enough free space.

This one to move system/arbitration mailboxes.
Get-Mailbox -Arbitration -Database <OldDatabase> | New-MoveRequest -TargetDatabase <NewDatabase>

Open in new window

Once all the above moved successfully you can delete the old database.
Sandeep KumarAssociate ConsultantCommented:
Visit to know how to reduce the size of Exchange server database EDB file.
Jeff GloverSr. Systems AdministratorCommented:
speaking from experience, DO NOT DO AN OFFLINE DEFRAG. This has not worked well since Exchange 2003 (and not great then). You will need enough disk space available for a new Database (you would need that anyway). Create a new Database. Move the user accounts there. If there are not many, you can do it all at once with powershell or you can do it in batches. Once all mailboxes are on the new DB, then move the arbitration mailboxes like MAS showed.
  Doing it this way never takes the users offline so you can do it during the day.

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
SysToolsData Expert - Recovery,Backup,MigrationCommented:
To Reduce the size of Exchange Server 2013 Database when EDB File size has grown too large. You can try following methods to reclaim the space:

1) First, create a new Mailbox database and move the data from Old Mailbox to New Mailbox.
2) Then, shrink EDB Database file by performing Offline defrag.
3) Move the location of the Mailbox Database.

You can use "Powershell Command" and "Exchange Control Panel" . You can visit :    for Complete Step by Step process.
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today

From novice to tech pro — start learning today.