zfsnap is a Free and open source script designed to make rolling ZFS snapshots easy. It is written in portable /bin/sh, and our aim is for zfsnap to run wherever ZFS is supported.
zfsnap follows the "Unix Philosophy." All the information it needs is stored directly in the snapshot's name; no database or special ZFS properties are needed. Care is taken to work with ZFS's utilities — rather than reimplement them.
zfsnap is fast and scalable. It can check tens-of-thousands of snapshots in seconds.