Friday, July 4, 2008

Is it possible to defragment a mounted information store?

After running ESEUTIL /P on one of the exchange servers we maintain, I am quickly realizing this will take a long time to complete, and of course I am hanging out at the "" exchange forums. Excellent place to hang out, so much to learn there. (- :

Here is a great question being asked by one of our member and I wanted to blog this here to share the point with all my friends.


Is it possible to defragment a mounted information store?
What would be the risk? What are the benefits if any?


This is a good question, and exchange _Geek provided you excellent MS link explaining the difference offline and online defrag. Most offend I get to asked same question , and therefore, I wanted to make sure when you read the MS article provided here, you will be clearly understand the difference offline and online defrag when it comes to exchange databases.

"During the offline defragmentation process, Eseutil.exe creates a new database. It copies only the in-use database records to the new database file, which results in a new compact database file. An offline defragmentation is the only method that reduces the physical file size of the databases"

The way it works as you see, exchange will create a new "EMTY" database and start copying the data from original database into this newly created DB, and at the end it will delete the original database which may contain white space (Space cannot be used by the database) and now you have a brad new DB which has only contains mail data.

It looks like getting when your car tires getting real dirty and old you ordering the new ones, but you are keeping your rims with the new tires. You still want to drive the car, when the work is being done (-:, no you cannot , you need to sit and wait, until the new tires put on the car and mechanic makes sure it is safe to drive

Enjoy your coffee until then (this happens when you use "ESEUTIL" with any of the switches)



Oz Ozugurlu

MVP (Exchange)


MCSE 2003, M+, S+, MCDST

Security+, Project +, Server +


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