A snapshot is a point-in-time copy of a filesystem or LUN. Snapshots can be created manually
or by setting up an automatic schedule. Snapshots initially consume no additional space, but as the
active share changes, previously unreferenced blocks will be kept as part of the last snapshot. Over
time, the last snapshot will take up additional space, with a maximum equivalent to the size of the
filesystem at the time the snapshot was taken.
Filesystem snapshots can be accessed over the standard protocols in the
.zfs/snapshot snapshot at the root of the filesystem. This directory is hidden by
default, and can only be accessed by explicitly changing to the .zfs directory.
This behavior can be changed in the Snapshot view, but may cause backup software to backup snapshots in addition to live data.
LUN Snapshots cannot be accessed directly, though they can be used as a rollback target or as the
source of a clone. Project snapshots are the equivalent of snapshotting all shares within the
project, and snapshots are identified by name. If a share snapshot that is part of a larger project
snapshot is renamed, it will no longer be considered part of the same snapshot, and if any snapshot
is renamed to have the same name as a snapshot in the parent project, it will be treated as part of
the project snapshot.
Shares support the ability to rollback to previous snapshots. When a rollback occurs, any
newer snapshots (and clones of newer snapshots) will be destroyed, and the active data will be
reverted to the state when the snapshot was taken. Snapshots only include data, not properties, so
any property settings changed since the snapshot was taken will remain.