Exchange database and backups continue to grow in size. 1

[IsilZha]

Hello, I'm trying to figure out why our exchange database and by association, backups, continue to grow in size day after day, even though we've cleared out large mailboxes. The problem is of course that eventually we're going to run out of space for backups (each backup is 50 GB now.)

A week ago we even cleared out a 12 GB mailbox (bot for our company's business, not a real user, not spam) - including the deleted items recovery (which the time has now expired on and would've been purged anyway) and the database size didn't decrease at all - in fact, the backup for that night showed that it once again actually grew in size, and has continued to do so over the last week.

Any ideas?

 

[wdoellefeld]

Deleting a mailbox or thining out active accounts doesn't reduce the size of the priv at all, it just free's up room inside it for more email. The physical size remains the same. To physically reduce the size you would need to do an offline defrag.


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[WhoKilledKenny]

Deleting mailboxes does not shrink the database. It just leaves whitespace where a mailbox once existed. To recoup size you need to run eseutil (which is a defrag utility for exchange). Do a search on Microsoft for your versions of exchange. READ INFORMATION CAREFULLY before attempting to recoup white space, make sure you clearly understand the instructions.

Jesse Hamrick

http://www.powershellpro.com

 

[pmyint]

Or alternatively you can create a new Mailbox Store and migrate the Mailboxes which will allow you to continue with business operations and clear DEAD white space in the EDB


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[xmsre]

If you clear the items out of a mailbox, they are retained for the deleted items retention interval. If you delete a mailbox, it is retained for 30 days.

I'd cut down the DIR, do a mailbox policy to clean out the items, wait for online maintenance and defrag to complete, then watch the 1221. After the space shows up as whitespace, delete the empty mailbox.

 

[IsilZha]

It's not really deleting mailboxes that I'm looking at for clearing space, but clearing out a lot of extra stuff in already existing mailboxes.

For instance, that 12 GB box we just deleted everything inside it, including the retained deleted items (the 7 day limit that's set as elapsed now anyway.)

Now my next question is, does it reuse that whitespace, or does that whitespace just sit there, taking up space with no use? Because since we emptied out that 12 GB mailbox the database has still continued to grow each day.

Thanks.

 

[pmyint]

No u will not recover that Whitespace.. unless u offline defrag or move to a new store..

BUT it will use that Whitespace inside the EDB


Thats why i ended up creating a new store and moving mailboxes

 

[ntinlin]

As XMSRE says you need to keep an eye on the 1221 events in event log. This will tell you how much white space is in the database. That whitespace WILL be used before the database starts growing again.

It is perfectly possible that your mailbox maintenance cycle is getting constantly interrupted and never completing due to backups, A/V scans etc. which would stop Exchange purging the old data.

Neill

 

[xmsre]

Whitespace within the EDB is reused before increasing the size of the EDB. If the amount of mail in existing mailboxes will increase (because they haven't reached their limits), or in other words the whitespace will be reused, then doing an offline defrag is counterproductive and can actually degrade performance. It's only when you are absolutely certian the whitespace will not be reused (you just imposed limits and removed a bunch of mail and the mailboxes will not grow beyond the new limits for example) that you would consider removing the whitespace. In that event, it's preferrable to movemailbox to a new store. Only if that option is not available, and there is a large amount of whitespace that will never be reused, is offline defrag worth considering.

 

[58sniper]

Keep in mind, too, that moving mailboxes to another store causes you to lose info in the dumpster.

Pat Richard
Microsoft Exchange MVP

 

[IsilZha]

Here's my new concern then. The database grows by roughly 50 MB daily. When we cleared out the at 12 GB box, the database still grew the same amount, and continues to grow by the same amount every day - it doesn't seem to be using that 12 GB of whitespace that should be there.

 

[xmsre]

FOr the whitespace to be available for reuse, the following must happen.

1. DIR must expire, then
2. Online maintenance must run and complete, then
3. Online defrag must run and complete

Even though you deleted 12GB of mail, 12GB may or may not have been removed. Exchange stores are SIS. If a message is sent to multiple recipients, it's stored once and each recipient gets a pointer to that copy. A single user deleting the item merely deletes a pointer. Only if the item is not referenced by any pointer will the deletion actually result in whitespace after the above process completes.

Then there's the issue of format. How are the messages arriving? MAPI or MIME? Is the increase in space really the EDB, or is it the STM?

 

[IsilZha]

hmm, ok, I did notice something else. The backups are growing more than the exchange databases. Now I've noticed that databases are not increasing in size, yet the backups are - and the main issue is the backup size.

 

[Zelandakh]

What are you backing up? Store or individual mailboxes? My guess would be the latter.