path: root/Documentation/mkfs.btrfs.txt
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authorQu Wenruo <>2014-04-02 16:29:37 +0800
committerDavid Sterba <>2014-04-22 14:15:24 +0200
commit7eb1c25e0564dea0f7edc32114f84cf8cdfefe27 (patch)
tree1c3bc0a1070254830335dcde1e259f04b5dfe00b /Documentation/mkfs.btrfs.txt
parent81066737e772ea3112ff2a399ca9072a76c650ee (diff)
btrfs-progs: Convert man page for mkfs.btrfs.
Convert man page for mkfs.btrfs. Signed-off-by: Qu Wenruo <> Signed-off-by: David Sterba <>
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+mkfs.btrfs - create a btrfs filesystem
+$$[-A|--alloc-start <alloc-start>]$$
+$$[-b|--byte-count <byte-count>]$$
+$$[-d|--data <data-profile>]$$
+$$[-n|--nodesize <nodesize>]$$
+$$[-l|--leafsize <leafsize>]$$
+$$[-L|--label <label>]$$
+$$[-m|--metadata <metadata profile>]$$
+$$[-s|--sectorsize <sectorsize>]$$
+$$[-r|--rootdir <rootdir>]$$
+$$[-O|--features <feature1>[<,feature2...>]]$$
+$$<device> [<device>...]$$
+is used to create a btrfs filesystem (usually in a disk partition, or an array
+of disk partitions).
+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.
+-A|--alloc-start <offset>::
+Specify the offset from the start of the device to start the btrfs filesystem. The default value is zero, or the start of the device.
+-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'.
+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.
+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.
+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
+Print the 'mkfs.btrfs' version and exit.
+Print help.
+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...
+'btrfs' is part of btrfs-progs. Btrfs filesystem is currently under heavy
+and not suitable for any uses other than benchmarking and review.
+Please refer to the btrfs wiki for
+further details.