Using a point-in-time copy as an intermediate stage in a tape backup
operation is one of the most common uses for snapshots. Even if the backup
software integrates with the application to allow online backups, (as is the
case with most common database and email applications), backups can still
impact application performance and vice-versa. If the backup is taken from a
point-in-time copy, the performance impact is lesser in both directions.
Similarly, for a remote mirroring configuration, the use of a point-in-time copy
as an intermediate stage isolates the application from the effects of WAN
latency in the remote mirroring process.