zfs-snapshot(8)

NAME

zfs-snapshot – create snapshots of ZFS datasets

SYNOPSIS

zfs snapshot [-r] [-o property=value]… dataset@snapname…

DESCRIPTION

Creates a snapshot of a dataset or multiple snapshots of different datasets.

Snapshots are created atomically. That is, a snapshot is a consistent image of a dataset at a specific point in time; it includes all modifications to the dataset made by system calls that have successfully completed before that point in time. Recursive snapshots created through the -r option are all created at the same time.

zfs snap can be used as an alias for zfs snapshot.

See the Snapshots section of zfsconcepts(7) for details.

-o property=value: Set the specified property; see zfs create for details.
-r: Recursively create snapshots of all descendent datasets

EXAMPLES

Example 1 : No Creating a ZFS Snapshot

The following command creates a snapshot named yesterday. This snapshot is mounted on demand in the .zfs/snapshot directory at the root of the pool/home/bob file system.

# zfs snapshot pool/home/bob@yesterday

Example 2 : No Creating and Destroying Multiple Snapshots

The following command creates snapshots named yesterday of pool/home and all of its descendent file systems. Each snapshot is mounted on demand in the .zfs/snapshot directory at the root of its file system. The second command destroys the newly created snapshots.

# zfs snapshot -r pool/home@yesterday

# zfs destroy -r pool/home@yesterday

Example 3 : No Promoting a ZFS Clone

The following commands illustrate how to test out changes to a file system, and then replace the original file system with the changed one, using clones, clone promotion, and renaming:

# zfs create pool/project/production
  populate /pool/project/production with data
# zfs snapshot pool/project/production@today
# zfs clone pool/project/production@today pool/project/beta
  make changes to /pool/project/beta and test them
# zfs promote pool/project/beta
# zfs rename pool/project/production pool/project/legacy
# zfs rename pool/project/beta pool/project/production
  once the legacy version is no longer needed, it can be destroyed
# zfs destroy pool/project/legacy

Example 4 : No Performing a Rolling Snapshot

The following example shows how to maintain a history of snapshots with a consistent naming scheme. To keep a week's worth of snapshots, the user destroys the oldest snapshot, renames the remaining snapshots, and then creates a new snapshot, as follows:

# zfs destroy -r pool/users@7daysago
# zfs rename -r pool/users@6daysago @7daysago
# zfs rename -r pool/users@5daysago @6daysago
# zfs rename -r pool/users@4daysago @5daysago
# zfs rename -r pool/users@3daysago @4daysago
# zfs rename -r pool/users@2daysago @3daysago
# zfs rename -r pool/users@yesterday @2daysago
# zfs rename -r pool/users@today @yesterday
# zfs snapshot -r pool/users@today