168 lines
5.2 KiB
Plaintext
168 lines
5.2 KiB
Plaintext
btrfs-filesystem(8)
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===================
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NAME
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----
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btrfs-filesystem - control btrfs filesystem
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SYNOPSIS
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--------
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*btrfs filesystem* <subcommand> <args>
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DESCRIPTION
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-----------
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*btrfs filesystem* is used to do the filesystem level control jobs, including
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all the regular filesystem operations like setting/getting label,
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resizing, defragment.
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SUBCOMMAND
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----------
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*df* [options] <path>::
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Show space usage information for a mount point.
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+
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`Options`
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+
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-b|--raw::::
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raw numbers in bytes, without the 'B' suffix
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-h::::
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print human friendly numbers, base 1024, this is the default
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-H::::
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print human friendly numbers, base 1000
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--iec::::
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select the 1024 base for the following options, according to the IEC standard
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--si::::
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select the 1000 base for the following options, according to the SI standard
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-k|--kbytes::::
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show sizes in KiB, or kB with --si
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-m|--mbytes::::
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show sizes in MiB, or MB with --si
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-g|--gbytes::::
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show sizes in GiB, or GB with --si
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-t|--tbytes::::
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show sizes in TiB, or TB with --si
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If conflicting options are passed, the last one takes precedence.
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*show* [--mounted|--all-devices|<path>|<uuid>|<device>|<label>]::
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Show the btrfs filesystem with some additional info.
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+
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If no option nor <path>|<uuid>|<device>|<label> is passed, btrfs shows
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information of all the btrfs filesystem both mounted and unmounted.
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If '--mounted' is passed, it would probe btrfs kernel to list mounted btrfs
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filesystem(s);
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If '--all-devices' is passed, all the devices under /dev are scanned;
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otherwise the devices list is extracted from the /proc/partitions file.
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*sync* <path>::
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Force a sync for the filesystem identified by <path>.
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*defragment* [options] <file>|<dir> [<file>|<dir>...]::
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Defragment file data and/or directory metadata *online*.
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+
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If '-r' is passed, files in dir will be defragmented recursively.
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The start position and the number of bytes to defragment can be specified by
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start and len using '-s' and '-l' options below.
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Any extent bigger than threshold given by '-t' option, will be considered
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already defragged.
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Use 0 to take the kernel default.
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You can also turn on compression in defragment operations.
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`Options`
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-v::::
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be verbose
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-c::::
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compress file contents while defragmenting
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-r::::
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defragment files recursively
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-f::::
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flush filesystem after defragmenting
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-s <start>::::
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defragment only from byte <start> onward
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-l <len>::::
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defragment only up to <len> bytes
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-t <size>::::
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defragment only files at least <size> bytes big
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+
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For <start>, <len>, <size> it is possible to append a suffix
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like 'k' for 1 KBytes, 'm' for 1 MBytes...
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+
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WARNING: defragmenting with kernels up to 2.6.37 will unlink COW-ed copies of data,
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don't use it if you use snapshots, have de-duplicated your data or made
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copies with `cp --reflink`.
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// Some wording are extracted by the resize2fs man page
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*resize* [<devid>:][+/-]<size>[gkm]|[<devid>:]max <path>::
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Resize a filesystem identified by <path> for the underlying device
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devid *online*. +
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The devid can be found with *btrfs filesystem show* and
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defaults to 1 if not specified.
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The <size> parameter specifies the new size of the filesystem.
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If the prefix + or - is present the size is increased or decreased
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by the quantity <size>.
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If no units are specified, the unit of the <size> parameter defaults to
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bytes. Optionally, the size parameter may be suffixed by one of the following
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units designators: \'K\', \'M', or \'G', kilobytes, megabytes, or gigabytes,
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respectively.
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+
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If \'max' is passed, the filesystem will occupy all available space on the
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device devid.
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The resize command does not manipulate the size of underlying
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partition. If you wish to enlarge/reduce a filesystem, you must make sure you
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can expand the partition before enlarging the filesystem and shrink the
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partition after reducing the size of the filesystem. This can done using
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`fdisk`(8) or `parted`(8) to delete the existing partition and recreate
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it with the new desired size. When recreating the partition make sure to use
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the same starting disk cylinder as before.
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*label* [<dev>|<mountpoint>] [<newlabel>]::
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Show or update the label of a filesystem.
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+
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[<device>|<mountpoint>] is used to identify the filesystem.
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If a newlabel optional argument is passed, the label is changed.
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NOTE: the maximum allowable length shall be less than 256 chars
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*usage* [options] <path> [<path>...]::
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Show detailed information about internal filesystem usage.
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`Options`
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+
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-b|--raw::::
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raw numbers in bytes, without the 'B' suffix
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-h::::
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print human friendly numbers, base 1024, this is the default
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-H::::
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print human friendly numbers, base 1000
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--iec::::
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select the 1024 base for the following options, according to the IEC standard
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--si::::
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select the 1000 base for the following options, according to the SI standard
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-k|--kbytes::::
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show sizes in KiB, or kB with --si
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-m|--mbytes::::
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show sizes in MiB, or MB with --si
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-g|--gbytes::::
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show sizes in GiB, or GB with --si
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-t|--tbytes::::
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show sizes in TiB, or TB with --si
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-T::::
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show data in tabular format
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If conflicting options are passed, the last one takes precedence.
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EXIT STATUS
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-----------
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*btrfs filesystem* returns a zero exit status if it succeeds. Non zero is
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returned in case of failure.
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AVAILABILITY
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------------
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*btrfs* is part of btrfs-progs.
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Please refer to the btrfs wiki http://btrfs.wiki.kernel.org for
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further details.
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SEE ALSO
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--------
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`mkfs.btrfs`(8),
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