Exchange 2003 Backup Process Flow

The Volume Shadow Copy Service (VSS) feature in Windows 2003 can be used to greatly reduce the time needed to back up and restore Exchange 2003.

The diagram shows how the normal backup process flow works. When a snapshot request is received from an Exchange backup application (called a “requestor”), VSS tells the Exchange writer to pause new transactions, finish current transactions, and flush all cached data to disk. VSS then tells the appropriate storage provider to initiate the snapshot process for the disk volumes containing the Exchange data. Once the snapshot is taken, VSS tells the Exchange writer that it can resume writing to disk.

To use this feature, the backup program must include an Exchange VSS requestor. Since the NTBackup program bundled with Windows Server has no such requestor, organizations must use third-party backup products. Most major backup and storage vendors for Windows plan to offer VSS support, and Veritas Software’s popular BackUp Exec product will be one of the first, available soon after Exchange 2003 ships.