Reduce the size of the EDB (Full Version)

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malinton -> Reduce the size of the EDB (11.Apr.2007 3:06:14 PM)

Hey all,

I am trying to figure out the best way to reduce the size of the edb database. I have read a number of articles and there are mixed reviews with ESEUTIL. Are there any other options that I could consider?

Regards



a.grogan -> RE: Reduce the size of the EDB (11.Apr.2007 4:03:22 PM)

Hiya, by the nature of the EDB database technology the only way to shrink the physical size is to use the ESEUTIL /D command, generally it is safe, all you need to do is ensure that you have a full good backup of your Exchange database prior to running ESEUTIL. You will also need to ensure that you have about 110% of the size of your database free on the drive to defrag the DB. Have a look here for full instructions http://support.microsoft.com/kb/192185 it is not recommended that ESEUTIL is run as a matter of schedule (e.g. once a week) but I would typically run ESEUTIL on my databases every 6 months or so (we use Enterprise Vault) therefore we end up with large amounts of whitespace.

Hope this helps

A



zbnet -> RE: Reduce the size of the EDB (12.Apr.2007 3:37:49 AM)

My first question is why?  Why do you want to reduce the size of the priv.edb?  How big is it now?  And how much white space has it got in it?  Without answers to those questions, it is impossible to offer you the best advice.

To find the quantity of white space in your db, look in the application event log for 1221 events written by the overnight online maintenance.  These will tell you how much white space there is in the db.  There is one entry for each db (priv and pub), so make sure you tell us the correct figure.



zbnet -> RE: Reduce the size of the EDB (12.Apr.2007 3:46:15 AM)

A seperate reply to Andy's post:

Why do you run an offline defrag every 6 months?  Oh, I know you said you run EV and so you end up with a lot of white space, but ask yourself: is the level of new mail being generated roughly in balance with the email being archived?  If so, then you have a faily steady state on Exchange.  Sure, you get lots of white space created when EV runs, but then new mail will fill up the white space again.  And if the server is set up correctly, then the nightly online maintenance is running to defrag the db pages anyway, thus ensuring the internals of the priv.edb file are kept clean.

Running a regular offline defrag is just ensuring your priv.edb grows and shrinks on the disk - you're moving your 'white space' outside the priv.edb, for it only to be reconsumed again later when the priv.edb needs to grow to accommodate it.  It's not like the offline defrag frees up disk space that you use for something else - you still leave it free, ready for thw priv.edb to grow again.  Oh, and it's eating into your spare time, when you could be spending more time with the family!

Just about the only time I would ever do an offline defrag is when I'd created a significant quantity of white space in a db (say by a mass mailbox migration) and I didn't anticipate the space being used up again any time soon.  Other than that, it's pretty much a waste of time.



a.grogan -> RE: Reduce the size of the EDB (12.Apr.2007 4:00:47 AM)

Hiya zb, in fairness I was just proving an answer to mailnation question.
Each Exchange admin has their own reasons as to why they complete such tasks such as a defrag. I used the Enterprise Vault example as one of my intial reasons for running an offline defrag, but there are others. My company has quite a high turn over of staff in certain areas, but unfortunatley the HR departments are not as quick to notify us of leavers therefore it is not uncommon to receive a report of leavers from our HR section every 5 months that contains around 300 - 400 people to remove (I don't know if you are familiar with Social Services deparments and temp workers). Combined with the vaulting and leavers this does create a require in my organisation for offline defrags.

Don't get me wrong, I appreciate the advice, and really take the point about spending time with the familiy (I think that we all do).



zbnet -> RE: Reduce the size of the EDB (12.Apr.2007 4:09:14 AM)

You're right in pointing out that every environment is different, and that admins need to treat their own environment individually.

I see some people advocating offline defrags as a matter of routine, and that needs to be avoided.  You're obviously evaluating your situation, which is the right thing to do.

Keep up the good work posting answers to these forums!
Great blog, BTW.



a.grogan -> RE: Reduce the size of the EDB (12.Apr.2007 4:38:42 AM)

Thanks zb, and thank you for the comment about the blog, its small but fun.
I agree totally with you about the advocation of offline defrag in some quarters, and when all is said and done it can potentially be risk to continously defrag - I enjoy posting here, and like the feedback.

Cheers,

A



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