btrfs - Man Page

a toolbox to manage btrfs filesystems

Examples (TL;DR)

Create subvolume: sudo btrfs subvolume create path/to/subvolume
List subvolumes: sudo btrfs subvolume list path/to/mount_point
Show space usage information: sudo btrfs filesystem df path/to/mount_point
Enable quota: sudo btrfs quota enable path/to/subvolume
Show quota: sudo btrfs qgroup show path/to/subvolume

Synopsis

btrfs [global] <group> [<group>...] <command> [<args>]

Description

The btrfs utility is a toolbox for managing btrfs filesystems. There are command groups to work with subvolumes, devices, for whole filesystem or other specific actions. See section Commands.

There are also standalone tools for some tasks like btrfs-convert(8) or btrfstune(8) that were separate historically and/or haven't been merged to the main utility. See section Standalone Tools for more details.

For other topics (mount options, etc) please refer to the separate manual page btrfs(5).

Command Syntax

Any command name can be shortened so long as the shortened form is unambiguous, however, it is recommended to use full command names in scripts. All command groups have their manual page named btrfs-<group>.

For example: it is possible to run btrfs sub snaps instead of btrfs subvolume snapshot. But btrfs file s is not allowed, because file s may be interpreted both as filesystem show and as filesystem sync.

If the command name is ambiguous, the list of conflicting options is printed.

Sizes, both upon input and output, can be expressed in either SI or IEC-I units (see numfmt(1)) with the suffix B appended. All numbers will be formatted according to the rules of the C locale (ignoring the shell locale, see locale(7)).

For an overview of a given command use btrfs command --help or btrfs [command...] --help --full to print all available options.

There are global options that are passed between btrfs and the group name and affect behaviour not specific to the command, e.g. verbosity or the type of the output.

--format <format>: if supported by the command, print subcommand output in that format (text, json)
-v|--verbose: increase verbosity of the subcommand
-q|--quiet: print only errors
--log <level>: set log level (default, info, verbose, debug, quiet)

The remaining options are relevant only for the main tool:

--help: print condensed help for all subcommands
--version: print version string

Commands

balance: Balance btrfs filesystem chunks across single or several devices. See btrfs-balance(8) for details.
check: Do off-line check on a btrfs filesystem. See btrfs-check(8) for details.
device: Manage devices managed by btrfs, including add/delete/scan and so on. See btrfs-device(8) for details.
filesystem: Manage a btrfs filesystem, including label setting/sync and so on. See btrfs-filesystem(8) for details.
inspect-internal: Debug tools for developers/hackers. See btrfs-inspect-internal(8) for details.
property: Get/set a property from/to a btrfs object. See btrfs-property(8) for details.
qgroup: Manage quota group(qgroup) for btrfs filesystem. See btrfs-qgroup(8) for details.
quota: Manage quota on btrfs filesystem like enabling/rescan and etc. See btrfs-quota(8) and btrfs-qgroup(8) for details.
receive: Receive subvolume data from stdin/file for restore and etc. See btrfs-receive(8) for details.
replace: Replace btrfs devices. See btrfs-replace(8) for details.
rescue: Try to rescue damaged btrfs filesystem. See btrfs-rescue(8) for details.
restore: Try to restore files from a damaged btrfs filesystem. See btrfs-restore(8) for details.
scrub: Scrub a btrfs filesystem. See btrfs-scrub(8) for details.
send: Send subvolume data to stdout/file for backup and etc. See btrfs-send(8) for details.
subvolume: Create/delete/list/manage btrfs subvolume. See btrfs-subvolume(8) for details.

Standalone Tools

New functionality could be provided using a standalone tool. If the functionality proves to be useful, then the standalone tool is declared obsolete and its functionality is copied to the main tool. Obsolete tools are removed after a long (years) depreciation period.

Tools that are still in active use without an equivalent in btrfs:

btrfs-convert: in-place conversion from ext2/3/4 filesystems to btrfs
btrfstune: tweak some filesystem properties on a unmounted filesystem
btrfs-select-super: rescue tool to overwrite primary superblock from a spare copy
btrfs-find-root: rescue helper to find tree roots in a filesystem

For space-constrained environments, it's possible to build a single binary with functionality of several standalone tools. This is following the concept of busybox where the file name selects the functionality. This works for symlinks or hardlinks. The full list can be obtained by btrfs help --box.

Exit Status

btrfs returns a zero exit status if it succeeds. Non zero is returned in case of failure.

Availability

btrfs is part of btrfs-progs. Please refer to the documentation at https://btrfs.readthedocs.io.