xref: /freebsd/sys/contrib/openzfs/man/man8/zfs-snapshot.8 (revision c57c26179033f64c2011a2d2a904ee3fa62e826a)
1.\"
2.\" CDDL HEADER START
3.\"
4.\" The contents of this file are subject to the terms of the
5.\" Common Development and Distribution License (the "License").
6.\" You may not use this file except in compliance with the License.
7.\"
8.\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9.\" or https://opensource.org/licenses/CDDL-1.0.
10.\" See the License for the specific language governing permissions
11.\" and limitations under the License.
12.\"
13.\" When distributing Covered Code, include this CDDL HEADER in each
14.\" file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15.\" If applicable, add the following below this CDDL HEADER, with the
16.\" fields enclosed by brackets "[]" replaced with your own identifying
17.\" information: Portions Copyright [yyyy] [name of copyright owner]
18.\"
19.\" CDDL HEADER END
20.\"
21.\" Copyright (c) 2009 Sun Microsystems, Inc. All Rights Reserved.
22.\" Copyright 2011 Joshua M. Clulow <josh@sysmgr.org>
23.\" Copyright (c) 2011, 2019 by Delphix. All rights reserved.
24.\" Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
25.\" Copyright (c) 2014, Joyent, Inc. All rights reserved.
26.\" Copyright (c) 2014 by Adam Stevko. All rights reserved.
27.\" Copyright (c) 2014 Integros [integros.com]
28.\" Copyright 2019 Richard Laager. All rights reserved.
29.\" Copyright 2018 Nexenta Systems, Inc.
30.\" Copyright 2019 Joyent, Inc.
31.\"
32.Dd March 16, 2022
33.Dt ZFS-SNAPSHOT 8
34.Os
35.
36.Sh NAME
37.Nm zfs-snapshot
38.Nd create snapshots of ZFS datasets
39.Sh SYNOPSIS
40.Nm zfs
41.Cm snapshot
42.Op Fl r
43.Oo Fl o Ar property Ns = Ns Ar value Oc Ns …
44.Ar dataset Ns @ Ns Ar snapname Ns …
45.
46.Sh DESCRIPTION
47Creates a snapshot of a dataset or multiple snapshots of different
48datasets.
49.Pp
50Snapshots are created atomically.
51That is, a snapshot is a consistent image of a dataset at a specific
52point in time; it includes all modifications to the dataset made by
53system calls that have successfully completed before that point in time.
54Recursive snapshots created through the
55.Fl r
56option are all created at the same time.
57.Pp
58.Nm zfs Cm snap
59can be used as an alias for
60.Nm zfs Cm snapshot .
61.Pp
62See the
63.Sx Snapshots
64section of
65.Xr zfsconcepts 7
66for details.
67.Bl -tag -width "-o"
68.It Fl o Ar property Ns = Ns Ar value
69Set the specified property; see
70.Nm zfs Cm create
71for details.
72.It Fl r
73Recursively create snapshots of all descendent datasets
74.El
75.
76.Sh EXAMPLES
77.\" These are, respectively, examples 2, 3, 10, 15 from zfs.8
78.\" Make sure to update them bidirectionally
79.Ss Example 1 : No Creating a ZFS Snapshot
80The following command creates a snapshot named
81.Ar yesterday .
82This snapshot is mounted on demand in the
83.Pa .zfs/snapshot
84directory at the root of the
85.Ar pool/home/bob
86file system.
87.Dl # Nm zfs Cm snapshot Ar pool/home/bob Ns @ Ns Ar yesterday
88.
89.Ss Example 2 : No Creating and Destroying Multiple Snapshots
90The following command creates snapshots named
91.Ar yesterday No of Ar pool/home
92and all of its descendent file systems.
93Each snapshot is mounted on demand in the
94.Pa .zfs/snapshot
95directory at the root of its file system.
96The second command destroys the newly created snapshots.
97.Dl # Nm zfs Cm snapshot Fl r Ar pool/home Ns @ Ns Ar yesterday
98.Dl # Nm zfs Cm destroy Fl r Ar pool/home Ns @ Ns Ar yesterday
99.
100.Ss Example 3 : No Promoting a ZFS Clone
101The following commands illustrate how to test out changes to a file system, and
102then replace the original file system with the changed one, using clones, clone
103promotion, and renaming:
104.Bd -literal -compact -offset Ds
105.No # Nm zfs Cm create Ar pool/project/production
106  populate /pool/project/production with data
107.No # Nm zfs Cm snapshot Ar pool/project/production Ns @ Ns Ar today
108.No # Nm zfs Cm clone Ar pool/project/production@today pool/project/beta
109  make changes to /pool/project/beta and test them
110.No # Nm zfs Cm promote Ar pool/project/beta
111.No # Nm zfs Cm rename Ar pool/project/production pool/project/legacy
112.No # Nm zfs Cm rename Ar pool/project/beta pool/project/production
113  once the legacy version is no longer needed, it can be destroyed
114.No # Nm zfs Cm destroy Ar pool/project/legacy
115.Ed
116.
117.Ss Example 4 : No Performing a Rolling Snapshot
118The following example shows how to maintain a history of snapshots with a
119consistent naming scheme.
120To keep a week's worth of snapshots, the user destroys the oldest snapshot,
121renames the remaining snapshots, and then creates a new snapshot, as follows:
122.Bd -literal -compact -offset Ds
123.No # Nm zfs Cm destroy Fl r Ar pool/users@7daysago
124.No # Nm zfs Cm rename Fl r Ar pool/users@6daysago No @ Ns Ar 7daysago
125.No # Nm zfs Cm rename Fl r Ar pool/users@5daysago No @ Ns Ar 6daysago
126.No # Nm zfs Cm rename Fl r Ar pool/users@4daysago No @ Ns Ar 5daysago
127.No # Nm zfs Cm rename Fl r Ar pool/users@3daysago No @ Ns Ar 4daysago
128.No # Nm zfs Cm rename Fl r Ar pool/users@2daysago No @ Ns Ar 3daysago
129.No # Nm zfs Cm rename Fl r Ar pool/users@yesterday No @ Ns Ar 2daysago
130.No # Nm zfs Cm rename Fl r Ar pool/users@today No @ Ns Ar yesterday
131.No # Nm zfs Cm snapshot Fl r Ar pool/users Ns @ Ns Ar today
132.Ed
133.
134.Sh SEE ALSO
135.Xr zfs-bookmark 8 ,
136.Xr zfs-clone 8 ,
137.Xr zfs-destroy 8 ,
138.Xr zfs-diff 8 ,
139.Xr zfs-hold 8 ,
140.Xr zfs-rename 8 ,
141.Xr zfs-rollback 8 ,
142.Xr zfs-send 8
143