btrfs-subvolume(8)

1BTRFS-SUBVOLUME(8)               Btrfs Manual               BTRFS-SUBVOLUME(8)
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NAME

6       btrfs-subvolume - manage btrfs subvolumes
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SYNOPSIS

9       btrfs subvolume <subcommand> [<args>]
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DESCRIPTION

12       btrfs subvolume is used to create/delete/list/show btrfs subvolumes and
13       snapshots.
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SUBVOLUME AND SNAPSHOT

16       A subvolume is a part of filesystem with its own and independent
17       file/directory hierarchy. Subvolumes can share file extents. A snapshot
18       is also subvolume, but with a given initial content of the original
19       subvolume.
20
21           Note
22           A subvolume in btrfs is not like an LVM logical volume, which is
23           block-level snapshot while btrfs subvolumes are file extent-based.
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25       A subvolume looks like a normal directory, with some additional
26       operations described below. Subvolumes can be renamed or moved, nesting
27       subvolumes is not restricted but has some implications regarding
28       snapshotting.
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30       A subvolume in btrfs can be accessed in two ways:
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32       ·   like any other directory that is accessible to the user
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34       ·   like a separately mounted filesystem (options subvol or subvolid)
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36       In the latter case the parent directory is not visible and accessible.
37       This is similar to a bind mount, and in fact the subvolume mount does
38       exactly that.
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40       A freshly created filesystem is also a subvolume, called top-level,
41       internally has an id 5. This subvolume cannot be removed or replaced by
42       another subvolume. This is also the subvolume that will be mounted by
43       default, unless the default subvolume has been changed (see subcommand
44       set-default).
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46       A snapshot is a subvolume like any other, with given initial content.
47       By default, snapshots are created read-write. File modifications in a
48       snapshot do not affect the files in the original subvolume.
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SUBCOMMAND

51       create [-i <qgroupid>] [<dest>/]<name>
52           Create a subvolume <name> in <dest>.
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54           If <dest> is not given, subvolume <name> will be created in the
55           current directory.
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57           Options
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59           -i <qgroupid>
60               Add the newly created subvolume to a qgroup. This option can be
61               given multiple times.
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63       delete [options] <subvolume> [<subvolume>...]
64           Delete the subvolume(s) from the filesystem.
65
66           If <subvolume> is not a subvolume, btrfs returns an error but
67           continues if there are more arguments to process.
68
69           The corresponding directory is removed instantly but the data
70           blocks are removed later. The deletion does not involve full commit
71           by default due to performance reasons (as a consequence, the
72           subvolume may appear again after a crash). Use one of the --commit
73           options to wait until the operation is safely stored on the media.
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75           Options
76
77           -c|--commit-after
78               wait for transaction commit at the end of the operation
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80           -C|--commit-each
81               wait for transaction commit after deleting each subvolume
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83       find-new <subvolume> <last_gen>
84           List the recently modified files in a subvolume, after <last_gen>
85           ID.
86
87       get-default <path>
88           Get the default subvolume of the filesystem <path>.
89
90           The output format is similar to subvolume list command.
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92       list [options] [-G [+|-]<value>] [-C [+|-]<value>]
93       [--sort=rootid,gen,ogen,path] <path>
94           List the subvolumes present in the filesystem <path>.
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96           For every subvolume the following information is shown by default.
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98           ID <ID> top level <ID> path <path> where path is the relative path
99           of the subvolume to the top level subvolume. The subvolume’s ID may
100           be used by the subvolume set-default command, or at mount time via
101           the subvolid= option. If -p is given, then parent <ID> is added to
102           the output between ID and top level. The parent’s ID may be used at
103           mount time via the subvolrootid= option.
104
105           Options
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107           -p
108               print parent ID.
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110           -a
111               print all the subvolumes in the filesystem and distinguish
112               between absolute and relative path with respect to the given
113               <path>.
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115           -c
116               print the ogeneration of the subvolume, aliases: ogen or origin
117               generation.
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119           -g
120               print the generation of the subvolume.
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122           -o
123               print only subvolumes below specified <path>.
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125           -u
126               print the UUID of the subvolume.
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128           -q
129               print the parent uuid of subvolumes (and snapshots).
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131           -R
132               print the UUID of the sent subvolume, where the subvolume is
133               the result of a receive operation
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135           -t
136               print the result as a table.
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138           -s
139               only snapshot subvolumes in the filesystem will be listed.
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141           -r
142               only readonly subvolumes in the filesystem will be listed.
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144           -G [+|-]<value>
145               list subvolumes in the filesystem that its generation is >=, ⟨
146               or = value. '+' means >= value, '-' means <= value, If there is
147               neither '+' nor '-', it means = value.
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149           -C [+|-]<value>
150               list subvolumes in the filesystem that its ogeneration is >=,
151               <= or = value. The usage is the same to -G option.
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153           --sort=rootid,gen,ogen,path
154               list subvolumes in order by specified items. you can add '+' or
155               '-' in front of each items, '+' means ascending, '-' means
156               descending. The default is ascending.
157
158               for --sort you can combine some items together by ',', just
159               like --sort=+ogen,-gen,path,rootid.
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161       set-default <id> <path>
162           Set the subvolume of the filesystem <path> which is mounted as
163           default.
164
165           The subvolume is identified by <id>, which is returned by the
166           subvolume list command.
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168       show <path>
169           Show information of a given subvolume in the <path>.
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171       snapshot [-r] <source> <dest>|[<dest>/]<name>
172           Create a writable/readonly snapshot of the subvolume <source> with
173           the name <name> in the <dest> directory.
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175           If only <dest> is given, the subvolume will be named the basename
176           of <source>. If <source> is not a subvolume, btrfs returns an
177           error. If -r is given, the snapshot will be readonly.
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179       sync <path> [subvolid...]
180           Wait until given subvolume(s) are completely removed from the
181           filesystem after deletion. If no subvolume id is given, wait until
182           all current deletion requests are completed, but do not wait for
183           subvolumes deleted meanwhile. The status of subvolume ids is
184           checked periodically.
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186           Options
187
188           -s <N>
189               sleep N seconds between checks (default: 1)
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EXIT STATUS

192       btrfs subvolume returns a zero exit status if it succeeds. A non-zero
193       value is returned in case of failure.
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AVAILABILITY

196       btrfs is part of btrfs-progs. Please refer to the btrfs wiki
197       http://btrfs.wiki.kernel.org for further details.
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