This article explains the two different strtegy available in the exchange 2000 and 2003 server. The Netbackup is the backup tool used for backup and restore in the windows environment with excellent features.
Backup exchange 2000/2003 in 2 ways: Online backup and Offline backup.
An Online backup is performed while the Information Store is still mounted and the Exchange server is operational. The Exchange is Online and available for transactions, therefore it still allows users to work without interruption. Online backups also automatically clear the database logs upon completion.
Another major advantage of the Online backup method is the fact that the Exchange store is checked for corruption at the file-system level. This check is done by verifying the checksums on each 4 KB (Kilobyte) block or page in the database. If there is a checksum failure, backup will terminate. Exchange will not allow you to back up an Exchange store with a wrong checksum in it.
Therefore, after an online backup is complete, you should check the Event Viewer to find out whether your Exchange store is corrupted. If you see a failed backup with a page read error event in Event Viewer, this may be an early indication of a problem in the database.
Offline backup is performed by shutting down the Exchange Information Store service and performing COPY procedures on the Exchange databases (Public Folder or Mailbox stores). Using an Offline Backup provides a method to restore the Exchange system to its last known state or specific "point in time", and is usually considered to be less attractive than the Online backup.
However, you may need to perform an Offline backup in the following situations:
* Your Online backup failed. You can complete an Offline backup in situations where an Online backup might fail (for example, due to an error such as a checksum1018 JET_errReadVerifyFailure).
* Your backup software does not support Exchange Online backup APIs, requiring you to dismount the Exchange 2000/2003 mailbox and public folder stores before you backup the server.
Some disadvantages to performing an Offline backup include:
* You must stop IS services (You do not need to stop the IS if you only want to backup the store, for that you can simply just dismount it. However if you want to backup the log files you do need to stop the IS service).
* Users will not be able to access their mailboxes during the offline backup.
* Log files that contain transactions already written to the database files will not be purged after the completion of the backup.
* The database is not checked for corruption during an Offline backup. You might have a corrupt database and backup sets that cannot be used to restore your server to full functionality.
* An increased chance of data loss due to files being copied to and from a backup location.