1SNAPPER(8) Filesystem Snapshot Management SNAPPER(8)
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6 snapper - Command-line program for filesystem snapshot management
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9 snapper [--global-opts] command [--command-opts] [command-arguments]
10 snapper {--help}
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14 Snapper is a command-line program for filesystem snapshot management.
15 It can create, delete and compare snapshots and undo changes done
16 between snapshots.
17 Snapper never modifies the content of snapshots. Thus snapper creates
19 read-only snapshots if supported by the kernel. Supported filesystems
20 are btrfs as well as snapshots of LVM logical volumes with
21 thin-provisioning.
22
24 Configurations
25 For each filesystem or subvolume that should be snapshotted by snapper,
26 a configuration file is required, see snapper-configs(5). The setup can
27 be done with the create-config command.
28 Snapshots
30 Snapper distinguishes three types of snapshots.
31 pre
33 Pre snapshots should always have a corresponding post snapshot. The
34 intention of pre/post snapshot pairs is to snapshot the filesystem
35 before and after a modification.
36 post
38 See pre type.
39 single
41 These snapshots have no special relationship to other snapshots.
42 Note that filesystem-wise all three types are the same.
44 Snapshot Description and Userdata
46 With each snapshot a description and some userdata can be associated.
47 The description is a string. The userdata is a list of key-value pairs
48 where the keys and values are strings.
49 Do not use non-ASCII characters for the snapshot description, userdata
51 or any other strings, unless you always use the UTF-8 character
52 encoding.
53 Automatic Snapshot Creation
55 Next to manual snapshot creation, snapshots are also created
56 automatically.
57 · A cron-job creates hourly snapshots.
59 · Certain programs like YaST and zypper create pre/post snapshot
61 pairs when modifying the system.
62 Cleanup Algorithms
64 Snapper provides several algorithms to clean up old snapshots. The
65 algorithms are executed in a daily cron-job. This can be configured in
66 the corresponding configurations files along with parameters for every
67 algorithm.
68 number
70 Deletes old snapshots when a certain number of snapshots is
71 reached.
72 timeline
74 Deletes old snapshots but keeps a number of hourly, daily, weekly,
75 monthly and yearly snapshots.
76 empty-pre-post
78 Deletes pre/post snapshot pairs with empty diffs.
79 The number and timeline cleanup algorithms can also try to keep the
81 space used by snapshots below a limit and the free space of the
82 filesystem above a limit. For the first condition quota must be setup,
83 see command setup-quota. Additional the NUMBER_LIMIT and TIMELINE_LIMIT
84 variables in the config file must have ranges (min- and max-value). The
85 algorithms will then make two passes:
86 1. Delete snapshots above the max-value independent of the snapshot
88 and filesystem space.
89 2. Delete snapshots above the min-value until the limits for the
91 snapshot and filesystem are reached.
92 The limit for the used space can be configured via the SPACE_LIMIT
94 variable. Note: Only snapshots that have a cleanup algorithm set are
95 taken into account when calculating the space used by snapshots. The
96 limit for the free space can be configured via the FREE_LIMIT variable.
97 Filters
99 Some files keep state information of the system, e.g. /etc/mtab. Such
100 files should never be reverted. To help users, snapper allows one to
101 ignore these files.
102 Each line in all files /etc/snapper/filters/*.txt specifies a pattern.
104 When snapper computes the difference between two snapshots it ignores
105 all files and directories matching any of those patterns by using
106 fnmatch(3) with the flag FNM_LEADING_DIR.
107 Note that filters do not exclude files or directories from being
109 snapshotted. For that, use subvolumes or mount points.
110
112 -q, --quiet
113 Suppress normal output. Error messages will still be printed,
114 though.
115 -v, --verbose
117 Increase verbosity.
118 --utc
120 Display dates and times in UTC.
121 --iso
123 Display dates and times in ISO format.
124 -t, --table-style
126 Specifies table style. Table style is identified by an integer
127 number.
128 -c, --config name
130 Use specified configuration instead of the default configuration.
131 The default configuration is named "root".
132 --no-dbus
134 Operate without a DBus connection.
135 Use with caution since a running snapperd will not know about
137 modifications made to the system.
138 -r, --root path
140 Operate on target root. Only works together with no-dbus and only
141 for some commands.
142 --version
144 Print version and exit.
145
147 Snapper provides a number of commands. Each command accepts the options
148 listed in the GLOBAL OPTIONS section. These options must be specified
149 before the command name. In addition, many commands have specific
150 options, which are listed in this section. These command-specific
151 options must be specified after the name of the command and before any
152 of the command arguments.
153 help
155 Show short help text.
156 list-configs
158 List available configurations.
159 create-config [options] subvolume
161 Create a new configuration for a filesystem or subvolume. For this
162 command you will likely need the global option --config, see GLOBAL
163 OPTIONS and CONCEPTS.
164 -f, --fstype fstype
166 Manually set filesystem type. Supported values are btrfs and
167 lvm. For lvm, snapper uses LVM thin-provisioned snapshots. The
168 filesystem type on top of LVM must be provided in parentheses,
169 e.g. lvm(xfs).
170 Without this option snapper tries to detect the filesystem.
172 -t, --template name
174 Name of template for the new configuration file.
175 delete-config
177 Delete a configuration for a filesystem or subvolume. For this
178 command you will likely need to global option --config, see GLOBAL
179 OPTIONS and CONCEPTS.
180 get-config
182 Displays the settings of the configuration.
183 set-config configdata
185 Changes the settings of the configuration. The settings configdata
186 are a list of key-value-pairs separated by spaces and the key and
187 value must be separated by an equal sign, e.g. "NUMBER_CLEANUP=yes
188 NUMBER_LIMIT=10". The value of SUBVOLUME and FSTYPE cannot be
189 changed.
190 list (ls) [options]
192 List snapshots.
193 -t, --type type
195 Selects type of snapshots to list. Possible values are all,
196 single and pre-post.
197 --disable-used-space
199 Disable display of used space.
200 Calculating the used space needs some time. Thus this option
202 can speedup the listing.
203 -a, --all-configs
205 List snapshots from all configs accessible by the user.
206 For each snapshot the output consists of several columns. Some need
208 explanation:
209 #, Pre # and Post #
211 The number of the snapshot.
212 For btrfs the number can be followed by a sign. A "-" indicates
214 that the snapshot is the currently mounted snapshot and a "+"
215 indicates that the snapshot will be mounted next time (It is
216 the btrfs default subvolume). If both conditions apply a "*" is
217 displayed.
218 Used Space
220 For btrfs the exclusive space of the btrfs quota group
221 corresponding to the snapshot.
222 Display of used space is automatically disabled if not
224 available, e.g. quota not enabled on btrfs.
225 create [options]
227 Create a new snapshot.
228 -t, --type type
230 Specifies the type of the new snapshot. Possible values are
231 single, pre and post.
232 --pre-number number
234 For post snapshots the number of the pre snapshot must be
235 provided.
236 -p, --print-number
238 Print number of the created snapshot.
239 -d, --description description
241 Description for the snapshot.
242 -c, --cleanup-algorithm cleanup-algorithm
244 Set the cleanup algorithm for the snapshot.
245 -u, --userdata userdata
247 Set userdata for the snapshot. The key-value pairs must be
248 separated by comma and the key and value must be separated by
249 an equal sign, e.g. requestid=42,user=arthur.
250 --command command
252 Create a pre and post snapshot and run command in between.
253 modify [options] number
255 Modify a snapshot.
256 -d, --description description
258 New description for snapshot.
259 -c, --cleanup-algorithm cleanup-algorithm
261 Set the cleanup algorithm for the snapshot.
262 -u, --userdata userdata
264 Set userdata for the snapshot. The key-value pairs must be
265 separated by comma and the key and value must be separated by
266 an equal sign, e.g. requestid=42,user=arthur.
267 delete (remove|rm) number | number1-number2
269 Delete a snapshot or a range of snapshots.
270 -s, --sync
272 Sync the filesystem after deleting the snapshots. The details
273 depend on the filesystem type.
274 Btrfs normally asynchronously frees space after deleting
276 snapshots. With this option snapper will wait until the space
277 once used by the deleted snapshots is actually available again.
278 Snapshot 0 cannot be deleted. For btrfs the currently mounted
280 snapshot and the snapshot that will be mounted next time (the btrfs
281 default subvolume) can also not be deleted.
282 mount number
284 Mount a snapshot. Not required for all filesystem types.
285 umount number
287 Unmount a snapshot. Not required for all filesystem types.
288 status [options] number1..number2
290 Compare the snapshots number1 and number2. This will show a list of
291 files and directories that have been created, modified or deleted
292 in the time between the two snapshots have been made.
293 -o, --output file
295 Write output to file file.
296 The output consists of a string encoding the status followed by the
298 filename. The characters of the status string are:
299 1. A "+" means the file was created, a "-" means the file was
301 deleted. A "c" means the content of the file has changed and a
302 "t" means the type of the file has changed (e.g. from regular
303 file to directory).
304 2. A "p" means the permissions are have changed.
306 3. An "u" means the user ownership has changed.
308 4. A "g" means the group ownership has changed.
310 5. A "x" means the extended attribute information has changed.
312 6. An "a" means the ACL information has changed.
314 If there is no change a "." is outputted.
316 diff [options] number1..number2 [files]
318 Compare the snapshots number1 and number2. This will show a diff of
319 the content of files and directories that have been created,
320 modified or deleted in the time between the two snapshots have been
321 made.
322 -i, --input file
324 Read files to diff from file file.
325 --diff-cmd command
327 Command used for comparing files. The default is /usr/bin/diff
328 --new-file --unified. The two files to compare are passed as
329 parameters to the command.
330 -x, --extensions options
332 Extra options passed to the diff command.
333 undochange [options] number1..number2 [files]
335 Undo changes done between snapshot number1 and number2.
336 -i, --input file
338 Read files for which to undo changes from file file.
339 rollback [options] [number]
341 Creates two new snapshots and sets the default subvolume. Per
342 default the system boots from the default subvolume of the root
343 filesystem. The exact actions depend on whether a number is
344 provided or not:
345 · Without a number, a first read-only snapshot of the default
347 subvolume is created. A second read-write snapshot of the
348 current system is created. The system is set to boot from the
349 second snapshot.
350 · With a number, a first read-only snapshot of the current system
352 is created. A second read-write snapshot is created of number.
353 The system is set to boot from the second snapshot.
354 Rollback is only supported with btrfs and requires a properly
356 configured system.
357 -p, --print-number
359 Print number of the second created snapshot.
360 -d, --description description
362 Description for the snapshot.
363 -c, --cleanup-algorithm cleanup-algorithm
365 Set the cleanup algorithm for the snapshot.
366 -u, --userdata userdata
368 Set userdata for the snapshot. The key-value pairs must be
369 separated by comma and the key and value must be separated by
370 an equal sign, e.g. requestid=42,user=arthur.
371 The rollback command also sets the description, the cleanup
373 algorithm and some userdata unless the values are specified on the
374 command line. This will automate cleanup of snapshots created by
375 rollbacks.
376 setup-quota
378 Sets up quota. Currently only supported with btrfs.
379 cleanup cleanup-algorithm
381 Run the cleanup algorithm cleanup-algorithm. Currently implemented
382 cleanup algorithms are number, timeline and empty-pre-post.
383 xadiff number1..number2 [files]
385 Compare the extended attributes between snapshot number1 and
386 number2. See examples below:
387 · +:user.foo for created attributes
389 · -:user.bar for removed attributes
391 · -+:security.selinux for modified attributes
393
395 Non-root users can be allowed to use a configuration by setting
396 ALLOW_USERS or ALLOW_GROUPS in the config file. For all operations to
397 work, the user must also be able to read and access the .snapshots
398 directory inside the subvolume. The .snapshots directory must be owned
399 by root and must not be writable by anybody else.
400 Here are some methods how to achieve that:
402 · Make the directory accessible for everyone:
404 chmod a+rx .snapshots
406 · Make the directory accessible for a group the user belongs to,
408 e.g.:
409 chown :users .snapshots
411 · Make the directory accessible for the user using ACLs, e.g.:
413 setfacl -m u:tux:rx .snapshots
415 The last method can be performed by snapper, see the SYNC_ACL setting
417 in snapper-configs(5).
418
420 /etc/sysconfig/snapper
421 Global configuration file.
422 /etc/snapper/configs
424 Directory containing configuration files.
425 /etc/snapper/config-templates
427 Directory containing configuration templates.
428 /etc/snapper/filters/*.txt
430 Filter files.
431 /var/log/snapper.log
433 Logfile. Please include this file in bug reports.
434
436 There is no mechanism to ensure consistency of the files while a
437 snapshot it made. E.g. the files of a database can be inconsistent
438 while the database is running.
439 Consistency after undochange is not guaranteed. E.g. when the creation
441 of a user is undone, there might still exist files from that user.
442 Support for individual filesystems, rollback and extended attributes
444 are compile-time options and may not be available.
445
447 http://snapper.io/
448
450 Arvin Schnell <aschnell@suse.com>
451
453 snapper-configs(5), snapper-zypp-plugin(8), pam_snapper(8), btrfs(8),
454 lvm(8), attr(5), acl(5)
4550.8.3 2018-10-29 SNAPPER(8)