Introducing Arcserve Backup Agents and Options › Using Agents › Agent for Open Files › Best Practices › Backing up a Small Amount of Data on a Large Volume

Backing up a Small Amount of Data on a Large Volume

The agent operates on a per-file basis. This means that each open file is processed as it is encountered. By contrast, VSS operates on a per-volume basis, which means that VSS must prepare the entire volume for the backup job before the backup job can begin. With this in mind, consider a backup consisting of 10 gigabytes of critical database files that reside on a 120 gigabyte hard disk.

• Using VSS, a snapshot of the entire 120 gigabyte volume must be taken, and each Writer with data on that volume must prepare its files (both open and closed) before the backup job can begin.
• Using the agent, if the files to be backed up are closed when the request for the backup is made, the backup can begin immediately. If there are any open files, the agent synchronizes them and allows Arcserve Backup to back them up.

For these reasons, when you are backing up a small amount of data (relative to the size of the volume on which it resides), using the agent to handle open files results in a much faster backup.