Exchange database defragmentation refers to rearranging mailbox store and public folder store data to fill database pages more efficiently, thereby eliminating unused storage space.
By default, online defragmentation occurs daily between 1:00 AM and 5:00 AM on servers running Exchange 2000. Online defragmentation automatically detects and destroys objects that are no longer being used. This process provides more database space without actually changing the file size of the databases that are being defragmented.
Note To increase the efficiency of defragmentation and backup processes schedule your maintenance processes and backup operations to run at different times.
The following are two ways to schedule database defragmentation:
- Use the Maintenance interval option on the Database tab of a mailbox store or public folder store object to schedule database defragmentation for an individual database.
- Use the Maintenance interval option on the Database (Policy) tab of a mailbox store or a public folder store policy to schedule database defragmentation for a collection of mailbox stores and public folder stores.
For information about how to create a mailbox store policy or public folder policy, see ôCreate a Mailbox Store Policyö and ôCreate a Public Folder Store
Policyö in the Exchange 2000 online documentation.
Offline defragmentation is sometimes necessary if you need to reduce the physical file size of the databases. Offline defragmentation involves using the ESE utility (ESEUTIL) to create a new database, copy the old database records to the new one, and discard unused pages, resulting in a new compact database file.
You should consider an offline defragmentation only if a large number of users are moved off the server running Exchange 2000.
Consider the following when defragmenting your Exchange databases with ESEUTIL:
- To configure ESEUTIL to rebuild the new defragmented database on an alternate location, run ESEUTIL with the /p switch. This switch allows you to preserve your original defragmented database (which allows you to revert back to your original database if necessary). Using this switch also significantly reduces the amount of time it takes to defragment a database.
- Because offline defragmentation alters the database pages completely, you should create new backups of the Exchange 2000 databases immediately after offline defragmentation. If you perform your Exchange database backups with Backup, create new Normal backups of your Exchange databases. If you do not create new Normal backups, earlier Incremental or Differential backups will not work because they reference database pages that were reordered by the defragmentation process.
The information in this article applies to:
- Microsoft Exchange Server 2003 Enterprise Edition
- Microsoft Exchange Server 2003 Standard Edition
- Microsoft Windows Small Business Server 2003, Premium Edition
- Microsoft Windows Small Business Server 2003, Standard Edition
- Microsoft Exchange 2000 Server
