MKFS.BTRFS(8)                              Btrfs Manual                             MKFS.BTRFS(8)



NAME
       mkfs.btrfs - create a btrfs filesystem

SYNOPSIS
       mkfs.btrfs [-A|--alloc-start '<alloc-start>'] [-b|--byte-count '<byte-count>'] [-d|--data
       '<data-profile>'] [-f|--force] [-n|--nodesize '<nodesize>'] [-l|--leafsize '<leafsize>']
       [-L|--label '<label>'] [-m|--metadata '<metadata profile>'] [-M|--mixed] [-s|--sectorsize
       '<sectorsize>'] [-r|--rootdir '<rootdir>'] [-K|--nodiscard] [-O|--features
       '<feature1>'[,'<feature2>'...]] [-U|--uuid '<UUID>'] [-h] [-V|--version] '<device>'
       ['<device>'...]

DESCRIPTION
       mkfs.btrfs is used to create a btrfs filesystem (usually in a disk partition, or an array
       of disk partitions).

       <device> is the special file corresponding to the device (e.g /dev/sdXX ). If multiple
       devices are specified, btrfs is created spanning across the specified devices.

OPTIONS
       -A|--alloc-start <offset>
           Specify the offset from the start of the device at which to start allocations in this
           btrfs filesystem. The default value is zero, or the start of the device. This option
           is intended only for debugging filesystem resize operations.

       -b|--byte-count <size>
           Specify the size of the resultant filesystem. If this option is not used, mkfs.btrfs
           uses all the available storage for the filesystem.

       -d|--data <type>
           Specify how the data must be spanned across the devices specified. Valid values are
           raid0, raid1, raid5, raid6, raid10 or single.

       -f|--force
           Force overwrite when an existing filesystem is detected on the device. By default,
           mkfs.btrfs will not write to the device if it suspects that there is a filesystem or
           partition table on the device already.

       -n|--nodesize <size>

       + -l|--leafsize <size>:: Specify the nodesize, the tree block size in which btrfs stores
       data. The default value is 16KB (16384) or the page size, whichever is bigger. Must be a
       multiple of the sectorsize, but not larger than 65536. Leafsize always equals nodesize and
       the options are aliases.

       -L|--label <name>
           Specify a label for the filesystem.

               Note
               <name> should be less than 256 characters.

       -m|--metadata <profile>
           Specify how metadata must be spanned across the devices specified. Valid values are
           raid0, raid1, raid5, raid6, raid10, single or dup.

           Single device will have dup set by default except in the case of SSDs which will
           default to single. This is because SSDs can remap blocks internally so duplicate
           blocks could end up in the same erase block which negates the benefits of doing
           metadata duplication.

       -M|--mixed
           Mix data and metadata chunks together for more efficient space utilization. This
           feature incurs a performance penalty in larger filesystems. It is recommended for use
           with filesystems of 1 GiB or smaller.

       -s|--sectorsize <size>
           Specify the sectorsize, the minimum data block allocation unit.

           The default value is the page size. If the sectorsize differs from the page size, the
           created filesystem may not be mountable by current kernel. Therefore it is not
           recommended to use this option unless you are going to mount it on a system with the
           appropriate page size.

       -r|--rootdir <rootdir>
           Specify a directory to copy into the newly created btrfs filesystem.

               Note
               -r option is done completely in userland, and don’t need root privilege to mount
               the filesystem.

       -K|--nodiscard
           Do not perform whole device TRIM operation by default.

       -O|--features <feature1>[,<feature2>...]
           A list of filesystem features turned on at mkfs time. Not all features are supported
           by old kernels.

           To see all features run
               mkfs.btrfs -O list-all

       -U|--uuid <UUID>
           Create the filesystem with the specified UUID, which must not already exist on the
           system.

       -V|--version
           Print the mkfs.btrfs version and exit.

       -h
           Print help.

UNIT
       As default the unit is the byte, however it is possible to append a suffix to the
       arguments like k for KBytes, m for MBytes...

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

SEE ALSO
       btrfs(8)



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