Shadow copy is a new feature of Windows Server 2003 that basically takes a snapshot of a file or folder at a given point in time, and stores that snapshot for a configured amount of time. While the value may not be evident at first, it should definitely gain attention when coupled with the age-old problem of tape backups with open files.

Tape backup programs routinely have problems because they cannot accurately or correctly backup data that is currently being used by a program. Many of these backup programs sell add-on programs for certain applications (such as Exchange for email or SQL for databases) in order to ensure proper backup of application-specific files, but these add-ons are expensive, and they don’t always work. As a result, the data is either incorrectly backed up, or not backed up at all. Shadow copy basically performs a backup of an entire volume, including files that are open, and it also ensures that all file changes that occur between the time the backup began and the time it finished, are also updated on the backup as well. NTBACKUP will not backup shadow copies by default, however other backup programs can be configured to do so, thus avoiding the additional costs of add-on utilities.