btrfs-subvolume(8) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | SUBVOLUME AND SNAPSHOT | SUBCOMMAND | EXAMPLES | EXIT STATUS | AVAILABILITY | SEE ALSO | COLOPHON

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

NAME         top

       btrfs-subvolume - manage btrfs subvolumes

SYNOPSIS         top

       btrfs subvolume <subcommand> [<args>]

DESCRIPTION         top

       btrfs subvolume is used to create/delete/list/show btrfs
       subvolumes and snapshots.

SUBVOLUME AND SNAPSHOT         top

       A subvolume is a part of filesystem with its own independent
       file/directory hierarchy. Subvolumes can share file extents. A
       snapshot is also subvolume, but with a given initial content of
       the original subvolume.

           Note
           A subvolume in btrfs is not like an LVM logical volume, which
           is block-level snapshot while btrfs subvolumes are file
           extent-based.

       A subvolume looks like a normal directory, with some additional
       operations described below. Subvolumes can be renamed or moved,
       nesting subvolumes is not restricted but has some implications
       regarding snapshotting.

       A subvolume in btrfs can be accessed in two ways:

       •   like any other directory that is accessible to the user

       •   like a separately mounted filesystem (options subvol or
           subvolid)

       In the latter case the parent directory is not visible and
       accessible. This is similar to a bind mount, and in fact the
       subvolume mount does exactly that.

       A freshly created filesystem is also a subvolume, called
       top-level, internally has an id 5. This subvolume cannot be
       removed or replaced by another subvolume. This is also the
       subvolume that will be mounted by default, unless the default
       subvolume has been changed (see subcommand set-default).

       A snapshot is a subvolume like any other, with given initial
       content. By default, snapshots are created read-write. File
       modifications in a snapshot do not affect the files in the
       original subvolume.

SUBCOMMAND         top

       create [-i <qgroupid>] [<dest>/]<name>
           Create a subvolume <name> in <dest>.

           If <dest> is not given, subvolume <name> will be created in
           the current directory.

           Options

           -i <qgroupid>
               Add the newly created subvolume to a qgroup. This option
               can be given multiple times.

       delete [options] <[<subvolume> [<subvolume>...]], delete
       -i|--subvolid <subvolid> <path>>
           Delete the subvolume(s) from the filesystem.

           If <subvolume> is not a subvolume, btrfs returns an error but
           continues if there are more arguments to process.

           If --subvolid is used, <path> must point to a btrfs
           filesystem. See btrfs subvolume list or btrfs
           inspect-internal rootid how to get the subvolume id.

           The corresponding directory is removed instantly but the data
           blocks are removed later in the background. The command
           returns immediately. See btrfs subvolume sync how to wait
           until the subvolume gets completely removed.

           The deletion does not involve full transaction commit by
           default due to performance reasons. As a consequence, the
           subvolume may appear again after a crash. Use one of the
           --commit options to wait until the operation is safely stored
           on the device.

           The default subvolume (see btrfs subvolume set-default)
           cannot be deleted and returns error (EPERM) and this is
           logged to the system log. A subvolume that’s currently
           involved in send (see btrfs send) also cannot be deleted
           until the send is finished. This is also logged in the system
           log.

           Options

           -c|--commit-after
               wait for transaction commit at the end of the operation.

           -C|--commit-each
               wait for transaction commit after deleting each
               subvolume.

           -i|--subvolid <subvolid>
               subvolume id to be removed instead of the <path> that
               should point to the filesystem with the subvolume

           -v|--verbose
               (deprecated) alias for global -v option

       find-new <subvolume> <last_gen>
           List the recently modified files in a subvolume, after
           <last_gen> generation.

       get-default <path>
           Get the default subvolume of the filesystem <path>.

           The output format is similar to subvolume list command.

       list [options] [-G [+|-]<value>] [-C [+|-]<value>]
       [--sort=rootid,gen,ogen,path] <path>
           List the subvolumes present in the filesystem <path>.

           For every subvolume the following information is shown by
           default:

           ID <ID> gen <generation> top level <ID> path <path>

           where ID is subvolume’s id, gen is an internal counter which
           is updated every transaction, top level is the same as parent
           subvolume’s id, and path is the relative path of the
           subvolume to the top level subvolume. The subvolume’s ID may
           be used by the subvolume set-default command, or at mount
           time via the subvolid= option.

           Options

           Path filtering

               -o
                   print only subvolumes below specified <path>.

               -a
                   print all the subvolumes in the filesystem and
                   distinguish between absolute and relative path with
                   respect to the given <path>.

           Field selection

               -p
                   print the parent ID (parent here means the subvolume
                   which contains this subvolume).

               -c
                   print the ogeneration of the subvolume, aliases: ogen
                   or origin generation.

               -g
                   print the generation of the subvolume (default).

               -u
                   print the UUID of the subvolume.

               -q
                   print the parent UUID of the subvolume (parent here
                   means subvolume of which this subvolume is a
                   snapshot).

               -R
                   print the UUID of the sent subvolume, where the
                   subvolume is the result of a receive operation.

           Type filtering

               -s
                   only snapshot subvolumes in the filesystem will be
                   listed.

               -r
                   only readonly subvolumes in the filesystem will be
                   listed.

               -d
                   list deleted subvolumes that are not yet cleaned.

           Other

               -t
                   print the result as a table.

           Sorting
               By default the subvolumes will be sorted by subvolume ID
               ascending.

               -G [+|-]<value>
                   list subvolumes in the filesystem that its generation
                   is >=, ⟨ or = value. '+' means >= value, '-' means <=
                   value, If there is neither '+' nor '-', it means =
                   value.

               -C [+|-]<value>
                   list subvolumes in the filesystem that its
                   ogeneration is >=, <= or = value. The usage is the
                   same to -G option.

               --sort=rootid,gen,ogen,path
                   list subvolumes in order by specified items. you can
                   add '+' or '-' in front of each items, '+' means
                   ascending, '-' means descending. The default is
                   ascending.

                   for --sort you can combine some items together by
                   ',', just like --sort=+ogen,-gen,path,rootid.

       set-default [<subvolume>|<id> <path>]
           Set the default subvolume for the (mounted) filesystem.

           Set the default subvolume for the (mounted) filesystem at
           <path>. This will hide the top-level subvolume (i.e. the one
           mounted with subvol=/ or subvolid=5). Takes action on next
           mount.

           There are two ways how to specify the subvolume, by <id> or
           by the <subvolume> path. The id can be obtained from btrfs
           subvolume list, btrfs subvolume show or btrfs
           inspect-internal rootid.

       show [options] <path>
           Show more information about a subvolume (UUIDs, generations,
           times, flags, related snapshots).

               /mnt/btrfs/subvolume
                       Name:                   subvolume
                       UUID:                   5e076a14-4e42-254d-ac8e-55bebea982d1
                       Parent UUID:            -
                       Received UUID:          -
                       Creation time:          2018-01-01 12:34:56 +0000
                       Subvolume ID:           79
                       Generation:             2844
                       Gen at creation:        2844
                       Parent ID:              5
                       Top level ID:           5
                       Flags:                  -
                       Snapshot(s):

           Options

           -r|--rootid <ID>
               show details about subvolume with root <ID>, looked up in
               <path>

           -u|--uuid UUID
               show details about subvolume with the given <UUID>,
               looked up in <path>

       snapshot [-r] [-i <qgroupid>] <source> <dest>|[<dest>/]<name>
           Create a snapshot of the subvolume <source> with the name
           <name> in the <dest> directory.

           If only <dest> is given, the subvolume will be named the
           basename of <source>. If <source> is not a subvolume, btrfs
           returns an error.

           Options

           -r
               Make the new snapshot read only.

           -i <qgroupid>
               Add the newly created subvolume to a qgroup. This option
               can be given multiple times.

       sync <path> [subvolid...]
           Wait until given subvolume(s) are completely removed from the
           filesystem after deletion. If no subvolume id is given, wait
           until all current deletion requests are completed, but do not
           wait for subvolumes deleted in the meantime.

           Options

           -s <N>
               sleep N seconds between checks (default: 1)

EXAMPLES         top

       Example 1. Deleting a subvolume

       If we want to delete a subvolume called foo from a btrfs volume
       mounted at /mnt/bar we could run the following:

           btrfs subvolume delete /mnt/bar/foo

EXIT STATUS         top

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

AVAILABILITY         top

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

SEE ALSO         top

       mkfs.btrfs(8), mount(8), btrfs-quota(8), btrfs-qgroup(8),

COLOPHON         top

       This page is part of the btrfs-progs (btrfs filesystem tools)
       project.  Information about the project can be found at 
       ⟨https://btrfs.wiki.kernel.org/index.php/Btrfs_source_repositories⟩.
       If you have a bug report for this manual page, see
       ⟨https://btrfs.wiki.kernel.org/index.php/Problem_FAQ#How_do_I_report_bugs_and_issues.3F⟩.
       This page was obtained from the project's upstream Git repository
       ⟨git://git.kernel.org/pub/scm/linux/kernel/git/kdave/btrfs-progs.git⟩
       on 2021-06-20.  (At that time, the date of the most recent commit
       that was found in the repository was 2021-05-13.)  If you
       discover any rendering problems in this HTML version of the page,
       or you believe there is a better or more up-to-date source for
       the page, or you have corrections or improvements to the
       information in this COLOPHON (which is not part of the original
       manual page), send a mail to man-pages@man7.org

Btrfs v4.6.1                   03/13/2021             BTRFS-SUBVOLUME(8)

Pages that refer to this page: tmpfiles.d(5)btrfs(8)btrfs-filesystem(8)btrfs-qgroup(8)btrfs-quota(8)