Disk fragmentation on Exchange db

[paulwood]

I really don't know if this is a problem or if it is, what the answer is. I have an Exchange server which shows 48% total fragmentation, report as follows.

Fragments File Size Most fragmented files
1,004 2,538 MB \exchangedb\priv1.edb
412 174 MB \exchangedb\priv1.stm
48 11,272 KB \exchangedb\pub1.edb
68 8,200 KB \exchangedb\pub1.stm
51 5,120 KB \exchangelogs\E00.log
52 5,120 KB \exchangelogs\E0000366.log
80 5,120 KB \exchangelogs\E0000367.log

There are just two folders, one for the data and one for the logs, a toal of 17 files. The server has only been running maybe three months. Any help would be appreciated.

 

[tony72000]

You want to dismount the private and public stores before you start the drive defragmenter.

NOTE: This will cause any one connected to loose data, so advise you do this in the evening / at night.

This is caused because the defragmenter cannot acces the files as they are in use.

However, this does not defragment the actual emails within the store files, this needs to be done using the Eseutil utility while the stores are not mounted.

 

[Zelandakh]

Step away from the defragmentation tool. Leave well alone unless you want a sleepless night of rebuilding your Exchange box.

eseutil /d will defrag your Exchange store to remove white space. Online defrag occurs during the maintenance interval while Exchange is running.

 

[58sniper]

I'm with Zelandakh. Don't defrag the mdbdata folder with the Windows defrag or a third party tool. Most of the better tools allow you to set exceptions, so you can exclude that folder.

Take the databases offline and run the eseutil /d if you must.

Pat Richard, MCSE MCSA:Messaging CNA
Want to know how email works? Read for yourself -

http://www.ietf.org/rfc/rfc2821.txt

 

[tony72000]

The 'eseutil' tool only defrags the data within the 'edb' (exchange database) file. It does not defrag the file itself. This is where you need to run the disk defragmenter with the store offline.

As per Microsofts own recommendations:

http://support.microsoft.com/kb/328804/en-us

I've done this for over 6 years with no problems and the exchange always runs a lot better for it.

 

[strongm]

That isn't a recommendation for a disk defragementation. it merely says that a disk defrag can be done, which is hardly the same thing.

The Exchange Server team do not recommend disk defragging (which is slightly different from recommending against it). Here's a quote from one of them:

The bottom line really is - you do not HAVE to file-level defrag the Exchange database drives. Exchange reads and writes to it's databases in very random fashion. Large sequential reads and writes will see much more improvement from file system defrag than Exchange databases will. But if you really WANT to do it - I would do it the old-fashioned way: move the databases off to some other volume, file system defrag the drive and then move the databases back... Or at least make sure you have a good backup, dismount the databases and file-system defrag then

 

[Zelandakh]

And since that recommendation is bottom line saying "Don't do it" and it comes from Nino, I'm happy to go with it.

 

[paulwood]

OK, I understand the issues to do with defragging and I think I would be inclined to take the exchange files off then defrag and put them back. I guess what my question then is, isn't fragmentation of 48% a bad thing, or is it likely that it's being mis-reported and there is no issue. If it is an issue, how on earth would it have happened with just those few files? I realise that with fewer files the percentage is increased quicker than with many, but should I be expecting results such as I posted above?