NT 4.0, Diskeeper, and Exchange 5.5 - defrag question

[mucous]

Hi,

I'm running NT 4.0 (SP6a) with Exchange 5.5.
When I run Diskeeper to defrag the hard drives on the server, the drive with all of our Exchange users is fairly heavily fragmented even after defrag is finished. I am wondering if all the fragmented files are from past users deleted from the server or something like that. I'm wondering if there's anyway to recover the many file fragments I'm seeing as diskeeper doesn't seem to be able to do much with them. As I mentioned, my theory is that the fragments are leftovers from past users. I've heard that Exchange has it's own clean up utility (esutil, or something like that)for cleaning the lost fragments. Is this right? and if so, are there any precautions I should be aware of before running it? I would really like to recover the disk space I see these files occupying.

Thanks for your advice.

 

[JohnCitron]

Hi,

Diskeeper is correct in not being able to defragment those files since those files are in use by the Exchange Server.

Diskeeper has no way of knowing or seeing the actual data that belongs to the Exchange Server because Exchange is really a huge transactional/journaled database. The data appears to Diskeeper as .dat and .log files only.

The Exchange Server's built-in defragger will defrag the database files and remove the 'white-space' left by deleted mailboxes.

Diskeeper is able to defrag files that are in use by defragging the server at boot time. Another thing to try, instead of the boot-time option, is to stop the Exchange services and then run DK normally.

Check the user manual/help file for more information for DK to make sure you can run it on your Exchange Server without mucking anything up.

Good luck,

John

 

[mucous]

JohnCitron,

Hey thanks for the info. The built in defragger in Exchange...is that the eseutil function? Do you know if it can be run anytime, or should it run during off hours?
I'm inclined to use it rather than Diskeeper, although if it can do the job with Exchange services shut down, I have no problems with that either. Will look into diskeeper and try to find out more.

Thanks again for your tips!

 

[JohnCitron]

It looks like the Essutil runs the built in defragger while the database is online. That is as far as I can tell. I am not an expert, by any means with Exchange; I just inherited the fine job of handling our Exchange server.

I know how you feel about messing with the Exchange database; let Exchange take care of its self rather than use a third party utility.

Good luck with DK. It is a really great product for print/file servers and workstations. Let us know how you make out with your findings.


John

 

[rstitzel]

http://www.microsoft.com/exchange/techinfo/administration/55/database.doc

Defragmenting Your Databases
One of the most important functions that the information store performs during regular online maintenance is reclaiming unused disk space by defragmenting the database. This feature has been fine-tuned since Exchange 5.0. In fact, Exchange 5.5 SP1 now includes a reporting tool that provides an estimate in the event log of how much free space is available in the information store after online defrag. This helps make the job of estimating how much disk space is needed a lot easier.
Note: The information store indicates in the event log when online defrag is started, interrupted, resumed, and completed. If you’re backing up the information store or performing an offline defrag, check the event log to make sure you’re not overlapping with online defrag. However, if online defrag is interrupted, the information store will resume the process at the next opportunity.
Online defragmentation does everything you need except shrink the size of the database files on disk. If you make major changes to your computer running Exchange (for example, if you move or delete a large number of mailboxes or remove a large number of newsgroups), you may consider performing an offline defrag by running Eseutil /d. However, in most cases, you should avoid running offline defrag because it’s an expensive operation.
When offline defrag runs, it creates a new database file and then copies all the data in the old file to the new file. This can take a lot of time. On average, it takes about one hour to defragment 5 to 10 GB. What’s more, you need enough free space for the offline defrag process to hold the new file. As a general rule, you should have 100 percent more free space than the amount you’re defragmenting.