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home | helpx minix x x minixx BTRFS-SUBVOLUME(8) Btrfs Manual BTRFS-SUBVOLUME(8) NAME btrfs-subvolume - manage btrfs subvolumes SYNOPSIS btrfs subvolume _subcommand_ [_args_] DESCRIPTION btrfs subvolume is used to create/delete/list/show btrfs subvolumes and snapshots. SUBVOLUME AND SNAPSHOT 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: o like any other directory that is accessible to the user o 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 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 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. 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. 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. -v|--verbose verbose output of operations. 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 subvolume _path_ regarding UUIDs, times, generations, flags and 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 rootid of the subvolume. -u|--uuid UUID of the subvolume. 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) EXIT STATUS btrfs subvolume returns a zero exit status if it succeeds. A non-zero value is returned in case of failure. AVAILABILITY btrfs is part of btrfs-progs. Please refer to the btrfs wiki http://btrfs.wiki.kernel.org for further details. SEE ALSO mkfs.btrfs(8), mount(8), btrfs-quota(8), btrfs-qgroup(8), Btrfs v5.4.1 01/09/2020 BTRFS-SUBVOLUME(8)
NAME | SYNOPSIS | DESCRIPTION | SUBVOLUME AND SNAPSHOT | SUBCOMMAND | EXIT STATUS | AVAILABILITY | SEE ALSO