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How do I shrink an 18gb Exchange Mailbox

Let me say this first.

The powers that be where I work do not want limitations on Exchange. Have explained what could happen. They do not care.

I have a user whose mailbox is 18 gb. What would the fastest way to clean this mailbox. User is having a hard time opening her Outlook.

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1 Solution
Randy DownsOWNERCommented:
Maybe this will help

Method 1: Reduce the size of the Exchange mailbox
If you reduce the size of the Exchange mailbox, the size of the .ost file will also be reduced. To reduce the size of the Exchange mailbox, do one or more of the following:
•Delete items in your mailbox.
•Archive items in your mailbox to one or more .pst files.
You can delete items or archive items manually. Alternatively, you can use Mailbox Cleanup. To use Mailbox Cleanup in Outlook 2007, click Mailbox Cleanup on the Tools menu. In the Mailbox Cleanup dialog box, you can use any one of the following features:
•View mailbox size.
•Find items that are older than a specified number of days.
•Find items that are larger than a specified size.
•Move old items to the archive file by clicking AutoArchive.
•Empty the deleted items folder.
•Delete all alternative versions of items in the mailbox.
Randy DownsOWNERCommented:
Method 3: Split your large .pst file into several smaller .pst files
Outlook 2007 does not have a built-in function to split a .pst file into multiple .pst files. Therefore, you have to use one of the following steps to split a large .pst file:
1.Use the Archive feature to move items to a new .pst file. To do this, follow these steps:
•In Outlook 2007, select your .pst file in the navigation pane.
•On the File menu, click Archive.
•In the Archive dialog box, click to select the Archive this folder and all subfolders check box, and then click a folder from the list.
•In the Archive items older than drop-down box, click a date.
•Click Browse, specify a path and a file name for the new .pst file, and then click OK.

Note The new .pst file is displayed in the Mail Folders list as Archive Folders.
If you want to change the display name for this .pst file, follow these steps:
•Right-click Archive Folders, and then click Properties.
•In the Archive Folders Properties dialog box, click Advanced.
•In the Personal Folders dialog box, enter the new display name in the Name box.
•Click OK two times to return to Outlook.
2.Use the Move to Folder feature to move items to a new .pst file. To do this, follow these steps:
•On the File menu, point to New, and then click Outlook Data File.
•In the New Outlook Data File dialog box, click Office Outlook Personal Folders File (.pst), and then click OK.
•Specify a path and a file name for the new .pst file.
•In the Create Microsoft Personal Folders dialog box, specify the display name of the .pst file in the Name box. This is the name that is used by Outlook in the Mail Folders list.
•In the folder that contains the items that you want to move to a new .pst file, click one or more items to move.
•On the Edit menu, click Move to Folder.
•In the Move Items dialog box, click New.
•In the Create New Folder dialog box, enter a name for the new folder in the Name box.
•Under Select where to place the folder, click the new .pst file, and then click OK.
•In the Move Items dialog box, make sure that the new folder in the new .pst file is selected, and then click OK.
jzainoAuthor Commented:
How does this effect the mailbox on the server?
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Randy DownsOWNERCommented:
As long as you are not leaving copies on the server the archived email only resides on the client.

I would try the procedure with a test mailbox to validate since working with the huge mailbox is going to take considerable time.

Randy DownsOWNERCommented:
Even if the above doesn't reduce the size of the mailbox within Exchange, it should improve performance for your user.

With such huge file a defrag might help too


To reduce the size of the .edb database file, you must perform an offline defragmentation with the Eseutil.exe utility (the eseutil /d command) against the .edb database file.

Note Online defragmentation does not reduce the size of .stm and .edb files.For additional information about defragmentation, click the article number below to view the article in the Microsoft Knowledge Base:
192185  (http://support.microsoft.com/kb/192185/EN-US/ ) XADM: How to Defragment with the ESEUTIL Utility (Eseutil.exe)
Have you tried:
1. create new Outlook profile without caching
2. use OWA

I've done this to show that it was a single large folder causing issues with Outlook.  We also upgraded to Office 2010, where Outlook supposedly deals with large single folders better.

Think of it this way...if Exchange can handle 70- 80- 100+GB of mail, the limitation shouldn't be in _which_ user accounts the data is assigned.  That's somewhat arbitrary.  The problem is with huge cache files getting corrupted, and searches, updates, and sorting within a large selection of data.  Like running a query on 2GB of data instead of querying only 100MB at a time.

We also do some manual archiving to PST files, but _never_ store them locally.  We put them in the user's home folder on the server, where they are backed up regularly.  A mistaken mass-deletion can be recovered to the last image taken with VSS.  Depending on your schedule, this could be 1 day or 12 hours or less.
Jamie McKillopCommented:

First, you need to decide the criteria you are going to use to clean the mailbox. Are you going to delete message over a certain age, etc? Depending on the criteria, you could use Managed Mailbox Policies to clean out unwanted data. This would be the easiest method.

After you clear out the mailbox, there are a couple of things to consider. First, if the user is in cached mode, the size of their OST fille will not change. What you should do is delete the OST file and let it rebuild. Second, the physical size on the Exchange database on disk will not decrease. After the period set in your deleted item retention time has expired, the Exchange online maintenance process will clear out the data and you will be left with white space in the database.

DO NOT perform an offline defrag of the database. An offline defrag will require a significant outage and isn't without risk. Due to the fact that you don't have limits, the whitespace will eventaully used up anyway. If you have cleared out a significant percentage of the database and you must reclaim the space, create a new mailbox store and move all the mailboxes from the original store to the new one. This not require a total outage and will carry far less risk. Once all the mailboxes have been moved, you can delete the original store.

DO NOT use PST files to archive email unless it is email you don't care about losing. PST files are notorious for becoming corrupt and they can be lost in a hard drive crash. You should never store PST files on a file share and access them across a network as they can become easily corrupted due to any slight issue with network connectivity. Exchange is the best place to store your email if you want to keep it protected.

>unless it is email you don't care about losing...

Brash statement.  Some of us dummies do back up files.  As notorious as the problems with PST are, we haven't lost a single PST file in ~8years, including old Server 2000 machines that were P4-based, and had crashed during the middle of the day with all files and databases open.  Anecdotal, perhaps.  But I would not classify myself as someone who doesn't care about losing email archives.

Until Exchange 2010, PST files have always been a method (whether officially MS-sanctioned or not) to store messages.  Especially when licensing and/or available server resources put limitations on database size.

Exchange 2010 has a "personal archive" feature that can link to a user's existing Exchange account and allow transfer back and forth from the mail client application.  Exchange admins can specify the personal archive store exist on a volume separate from the main Exchange database.  More/cheaper storage that can be added without disrupting Exchange, and will remove the PST problems.
Jamie McKillopCommented:
Most users do not backup files. Even if you did run backups, you would still lose any data created between backups. You are taking a risk by storing email in PSTs, period. if you've worked in any large scale environments and havn't lost a single PST in 8 years, you are the luckiest person on earth. Ask any Exchange admin with significant erperience in an enterprise environment how they feel about PST files and they will tell you the same thing I am. If you work in any environment where you are bound by legal or regulatory requirements for data retention and integrity, you will find PST storage of email is not an option.

Just because things were done a certain way in the past doesn't make it right to do it now. Hard drive space is relatively cheap, especially with Exchange 2010 where you can get away with using low performance disks. Exchange 2010's archive is not the same as PST files. The Exchange 2010 archive is still an Exchange database with all the same protection as a "normal" database. Keep your important data inside Exchange, not in PST files.

I'm looking forward to Exch.2010 for just this purpose.  Putting archives back online will eliminate headaches.  But I'm confused...if a PST is an "archive", then corrupting one is a non-issue, as it can be restored from backup.  Even moved/deleted messages can be recovered from the original Exchange database if the PST tanks before the next backup.

We are a small shop, less than 60GB on Exchange.  Scaling up I can see as a headache, I agree.  Electronic discovery is a bigger issue we're not required to deal with.  We have tested SQL solution offline from the Exchange database using GFI.  Permission control is there, as well no impact by Exchange users deleting items (and retention policies cleaning up after them).  100% retention, and audited access.  No mounting of accounts, and no ability to send out as the users...it's just static message traffic.

But, this sounds like a mail client issue, not the total space attributed to one user.

jzaino, what client is being used?  Outlook - what version?  Did you already create a new profile to eliminate or recreate the local cache?
Jamie McKillopCommented:
You can't rely on Exchange backups to recover items that are deleted from a mailbox (the archive process is essentially a copy/delete). You can use recover deleted items up to the deleted item recovery period. So, if you have your deleted item recovery set at 30 days and a user loses his PST file in a hard drive crash, you could use recover deleted items to recover anything he archived in the past 30 days. Anything beyond that time interval couldn't be recovered this way. You would need to go to your Exchange backups to get the rest. The issue you have is what dates did his PST span? You are going to have to do a restore for every day of the interval the PST spans because if he has set Outlook to archive once per day, restoring every backup in the interval is the only way to recover everything. This is going to be a monumental task.

All interesting and some very valid points the other EE members made, but lets step back from this for a moment and find out what you mean when you say "User is having a hard time opening her Outlook." ?

1. If you are connecting to Exchange in cached mode, turn the cache off, kill the OST and reconnect without cache turned on, does it work faster?  

2. If yes to # 1, then re-enable cache and an new OST will be created (be sure you deleted the old one first)  Now it will take some time to rebuild the OST but when its done you should be just as fast as a direct connect.  If not then I would look at the machine that's being used or consider not using cached mode for this user

3. if in step 1 its still slow when you connect I would explain a bit more about the issues the customer is having.  Could be the data need to be arranged into folders, i.e. if its 18GB and most is sitting directly in the Inbox and Sent folders then you need to create folders and organize the data because the more items you have in a folder the longer it takes the system to process that folder.

4. If none of the above work you could have a problem with that mailbox and I would suggest doing a move mailbox of the user to a new database.
Alexei Kuznetsov (Outlook MVP)CEOCommented:
I believe this user has a tons of attachments. So the most effective way is to cut these attachments replacing them with links. There is a free tool that can help: Replace Attachments with Links.
Thanks for the points and glad I was able to assist

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