Snapshot

A rapid, point-in-time image of a volume created initially on the same disk as the original by duplicating metadata rather than copying the full data set. Snapshots are often used to protect against data corruption (viruses, etc.) or to create test or pre-production environments. Snapshots are also often used as a first step for creating non-disruptive point-in-time backups, and for copying data sets to a second disk to create a full duplicate copy of the volume.