Exchange Database Defragmentation process. Complete Explanation
What is database defragmentation?
Database defragmentation is procedure for restoring the
white space which is available in mailbox database.
Data is stored in pages in contiguous order in exchange
mailbox database and on regular basis mailbox database size keep increasing because
many reasons for example adding mailboxes to the mailbox database right. In one
fine day you may observe that disk space is very less and you want to reduce
the database size. There are two options are available here, you to vacate the
mailboxes which are available in respective database, this activity doesn’t required
any down time. If you’re having free disk space on other drive you can do this
activity with less challenges.
Suppose you do not have alternate drive to move
mailboxes in that case you have option
called ‘database defragmentation’ this is nothing but arranging data pages in contiguous
order in respective database by doing this process occupied white space will be
released and you will gain free space on drive.
Let us see know how to calculate white space, execute the
below command, you can see the white space in availableNewMailboxSpace column
Before starting defragmentation process ensure that mailbox
database need to dismount and ensure you have enough free space available on any
drive.
For example database size is 19.26GB and white space size is 6.103GB to do this
defragmentation of this database 19.26-6.1=13.5+1=14.5 GB free space required
approximately 15GB free space required
Why this much free space required or equivalent free space
required?
During the defragmentation process, exchange will create a
temporary defrag file to arrange data in contagiously and once the defragmentation
process completes then exchange will delete the original database copy and
replaces this tempdefrag file to the original database location. No need worry
on this process its automatic exchange will do this.
In case you already started the defragmentation process
without checking the free space in that case what will happen?
If you already started the process without checking the free
space or you do not have sufficient space don’t panic let it run the process,
if no enough free space available then defragmentation process cancels and it
will not cause any problem to your database.
You have free space on other drive but not in C drive?
In general we will initiate the defragmentation process and
temp file location automatically chosen to C drive (C:\program
files\Microsoft\Exchange Server\V14\Bin or anywhere in C). in case you do not
have free space on C drive and you enough free space on another drive then use
/t switch to save temp file in another drive. I will show you in below.
I need to do defragmentation of the database but I have no
enough free space on C drive but I have free space on E drive.
Execute the command as shown below such as eseutil/d “F:\dumpster
Database\DB\dumpster database.edb” /t “E:\tempde\tempdefrag.edb”
This will crete temp edb database in E drive, once process
completed it will automatically replaces in original edb location
Hope you learned the exchange defragmentation process please
feel free to revert if you have questions
