BTRFS-FILESYSTEM(8)                        Btrfs Manual                       BTRFS-FILESYSTEM(8)



NAME
       btrfs-filesystem - control btrfs filesystem

SYNOPSIS
       btrfs filesystem <subcommand> <args>

DESCRIPTION
       btrfs filesystem is used to do the filesystem level control jobs, including all the
       regular filesystem operations like setting/getting label, resizing, defragment.

SUBCOMMAND
       df [options] <path>
           Show space usage information for a mount point.

           Options

           -b|--raw
               raw numbers in bytes, without the B suffix

           -h
               print human friendly numbers, base 1024, this is the default

           -H
               print human friendly numbers, base 1000

           --iec
               select the 1024 base for the following options, according to the IEC standard

           --si
               select the 1000 base for the following options, according to the SI standard

           -k|--kbytes
               show sizes in KiB, or kB with --si

           -m|--mbytes
               show sizes in MiB, or mB with --si

           -g|--gbytes
               show sizes in GiB, or gB with --si

           -t|--tbytes
               show sizes in TiB, or tB with --si

       If conflicting options are passed, the last one takes precedence.

       show [--mounted|--all-devices|<path>|<uuid>|<device>|<label>]
           Show the btrfs filesystem with some additional info.

           If no option nor <path>|<uuid>|<device>|<label> is passed, btrfs shows information of
           all the btrfs filesystem both mounted and unmounted. If --mounted is passed, it would
           probe btrfs kernel to list mounted btrfs filesystem(s); If --all-devices is passed,
           all the devices under /dev are scanned; otherwise the devices list is extracted from
           the /proc/partitions file.

       sync <path>
           Force a sync for the filesystem identified by <path>.

       defragment [options] <file>|<dir> [<file>|<dir>...]
           Defragment file data and/or directory metadata online.

           If -r is passed, files in dir will be defragmented recursively. The start position and
           the number of bytes to defragment can be specified by start and len using -s and -l
           options below. Any extent bigger than threshold given by -t option, will be considered
           already defragged. Use 0 to take the kernel default. You can also turn on compression
           in defragment operations.

           Options

           -v
               be verbose

           -c
               compress file contents while defragmenting

           -r
               defragment files recursively

           -f
               flush filesystem after defragmenting

           -s <start>
               defragment only from byte <start> onward

           -l <len>
               defragment only up to <len> bytes

           -t <size>
               defragment only files at least <size> bytes big

               For <start>, <len>, <size> it is possible to append a suffix like k for 1 KBytes,
               m for 1 MBytes...

                   Warning
                   defragmenting with kernels up to 2.6.37 will unlink COW-ed copies of data,
                   don’t use it if you use snapshots, have de-duplicated your data or made copies
                   with cp --reflink.

       resize [<devid>:]<size>[gkm]|[<devid>:]max <path>
           Resize a filesystem identified by <path> for the underlying device devid online.

           The devid can be found with btrfs filesystem show and defaults to 1 if not specified.
           The <size> parameter specifies the new size of the filesystem. If the prefix + or - is
           present the size is increased or decreased by the quantity <size>. If no units are
           specified, the unit of the <size> parameter defaults to bytes. Optionally, the size
           parameter may be suffixed by one of the following units designators: 'K', 'M', or 'G',
           kilobytes, megabytes, or gigabytes, respectively.

           If 'max' is passed, the filesystem will occupy all available space on the device
           devid.

           The resize command does not manipulate the size of underlying partition. If you wish
           to enlarge/reduce a filesystem, you must make sure you can expand the partition before
           enlarging the filesystem and shrink the partition after reducing the size of the
           filesystem. This can done using fdisk(8) or parted(8) to delete the existing partition
           and recreate it with the new desired size. When recreating the partition make sure to
           use the same starting disk cylinder as before.

       label [<dev>|<mountpoint>] [<newlabel>]
           Show or update the label of a filesystem.

           [<device>|<mountpoint>] is used to identify the filesystem. If a newlabel optional
           argument is passed, the label is changed. NOTE: the maximum allowable length shall be
           less than 256 chars

EXIT STATUS
       btrfs filesystem 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 btrfs wiki http://btrfs.wiki.kernel.org
       for further details.

SEE ALSO
       mkfs.btrfs(8),



Btrfs v3.17                                 11/22/2014                        BTRFS-FILESYSTEM(8)