In Exchange 2003, databases grow, and can get fragmented. It’s been nearly 6 years since it was released. Many people moved to Exchange 2003, and since may want to migrate to another new Exchange environment.
Either way, Exchange maintenance is important.
First, by default Exchange 2003 will have Online Defragmentation and it occurs daily between 1A and 5A. It’s online, so it’s OK if users hit their mailboxes during this time. It does not mess with e-mail. Every time someone accesses their mailbox, the defragmentation will pause, and then begin again once it notices that the mailboxes are idle again.
Secondly, there is something called Offline Defragmentation. Offline Defragmentation involves using a utility called Eseutil.exe (Exchange Server Database Utility). This utility can do some other things, but in this instance you can use it for defragmentation and shrinking down the size of the actual database. When using offline defragmentation, your databases must be offline.
According to Microsoft, the only times that you should use Offline Defragmentation is when:
- After performing a database repair (using the command Eseutil /p)
- After moving a significant amount of data from an Exchange Server database
- If instructed to do this when you are working with Microsoft Product Support Services, or when troubleshooting a specific problem and the existing documentation calls for an offline defragmentation.
NOTE:
- To determine how much space you will regain after the offline defragmentation of the database, check event 1221 in the Exchange server’s Application log. You should also consider the time factor when performing an offline defragmentation of the database because it is a lengthy process.
- It is also important to note that the offline defragmentation requires about 110% of the space of the original database to succeed. This is because the Eseutil tool actually creates a new database file, in addition to the original database file. Both files have to coexist on the disk. It is possible however, to redirect the temporary database file to a different hard disk by using the Eseutil /t switch
- Immediately create a backup after you initiate an offline defrag
For more good information, please see:
http://technet.microsoft.com/en-us/library/aa998687%28EXCHG.65%29.aspx