A snapshot provides a consistent point-in-time image of a VxFS file system. A snapshot can be accessed as a read-only mounted file system to perform efficient online backups of the file system. Snapshots implement copy-on-write semantics that incrementally copy data blocks when they are overwritten on the snapped file system.

See About snapshot file systems.

Snapshots for cluster file systems extend the same copy-on-write mechanism for the I/O originating from any node in the cluster.