Exchange 2003 - Questions of Offline Defragment Planning

Posted on 2008-06-16
Last Modified: 2011-09-20
Server is Windows SBS 2003 SP2 + Exchange 2003 SP2

We need to reduce the file size of Private Information Store (46gb now). The store have some useless mailbox which used 15gb.  We have 91gb free space on hard disk.

We planning to :
1) Use NTBackup to backup the information store files
2) Purge a mailbox which contain 15gb email.
3) Read Event viewer to confirm white space has been increased. (Should be increased 15gb)
4) dismount the mail store
5) Run:   eseutil /d /p "c:\program files\exchsrvr\mdbdata\priv1.edb" /t"c:\tempdfg.edb"
6) Mount it when offline defragment completed
7) file size of information store should be reduced 15gb

Question A)
Is above steps and command correct?

Question B)
How long does the offline defragment need?  Someone said 1gb per hour, but someone said 4g, 5g, 9g
The time is depending on mail store file size or only the whilte space size?

Question C)
We need to do repair after offline defragment ?

Thank you.
Question by:nekosan-zoippe
  • 2
LVL 25

Expert Comment

ID: 21791640
A)  No, you will need to have online maintenance run (which runs at night) so you would need to allow an overnight gap between 2 and 3

B)  It depends, between 1GB and 9GB per hour, but it averages at about 4GB - I need to test the time (from another question) but I am pretty sure it is based on the non whitespace (so your 46GB file with 15GB whitespace would be 31GB to defrag).

C)  Not necessarily.  The full guide is here ->

One thing I would add - why are you bothering to do an offline defrag?  You are only saving a small amount of space, you gain nothing by doing this if you have enough freespace.

LVL 70

Expert Comment

ID: 21791661
The steps are correct, its difficult to estimate how long it will take - depends on the processor etc but MS estimate 9Gb/Hr - See

No repair is required

Author Comment

ID: 21791738
Dear kieran_b,

We found more useless mailbox can be purge. So the Purge size is 30gb.

1) How long needed between step 2 and 3 ? (If purged 30gb mailbox)

2) If we can purge that 30gb mailbox. So the defragment time is (46-30)/4 = 4 hours ? (Assume 4gb per hour)

Because we need to speed up Backup/Restore time (NTBackup) and backup weekly (and daily increment backup). So we concern on the file size and backup time. (It need 3-4 hour to backup now and need more time for restore)

We wanna speed it up to reduce the recovery time while server problem occur. And we afraid the hard disk will be full later. (As the mail db is 4xgb)

Also, there have 15-30gb useless mailbox in db. (Because we have other useless mailbox too).

So we wanna reduce it and let everything smooth then before.

Because our server have 91gb free space only. If the mail db size keep increase, our hdd will be full....
LVL 25

Accepted Solution

kieran_b earned 125 total points
ID: 21791913
1) Online maintenance runs each night between 12 and 5am - you can force it to run earlier if you wish.  Also, make sure that you have deleted mailbox retention set to zero, and a full backup done BEFORE doing online maintenance.  Check each morning for event 1221 in the application log, it will tell you what the freespace (which should be called whitespace) is.

2) That would be my estimate, but I would prepare yourself for up to 11 hours (incase I am wrong and it does the whole data size, so 46/4 - i don't think it does, and would love to know how long it takes you - please time it :))

>>Because we need to speed up Backup

Excellent reason.

>>If the mail db size keep increase, our hdd will be full....

Well, Exchange will limit you to 75GB, but I see your point.

A word of advice though, between steps 4 and 5, make a backup copy of the physical EDB and STM files somewhere else - another partition, an external drive - anything.  If something does go wrong, you can easily get it back.  You could also get rid of the "/p /t"c:\tempdfg.edb"" from your command if you do that.

Good luck


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