|
|
| (4 intermediate revisions by one user not shown) |
| Line 1: |
Line 1: |
| − | =btrfs-check(8) manual page=
| |
| | {{GeneratedManpage | | {{GeneratedManpage |
| | |name=btrfs-check}} | | |name=btrfs-check}} |
| − |
| |
| − | ==NAME==
| |
| − | btrfs-check - check or repair an unmounted btrfs filesystem
| |
| − |
| |
| − | ==SYNOPSIS==
| |
| − |
| |
| − | <p><b>btrfs check</b> [options] <em><device></em></p>
| |
| − | ==DESCRIPTION==
| |
| − |
| |
| − | <p>The filesystem checker is used to verify structural integrity of a filesystem
| |
| − | and attempt to repair it if requested. The filesystem must be unmounted.</p>
| |
| − | <p>By default, <b>btrfs check</b> will not modify the device but you can reaffirm that
| |
| − | by the option <em>--readonly</em>.</p>
| |
| − | <p><b>btrfsck</b> is an alias of <b>btrfs check</b> command and is now deprecated.</p>
| |
| − | <blockquote><b>Warning:</b>
| |
| − | Do not use <em>--repair</em> unless you are adviced to by a developer, an
| |
| − | experienced user or accept the fact that <em>fsck</em> cannot possibly fix all sorts
| |
| − | of damage that could happen to a filesystem because of software and hardware
| |
| − | bugs.</blockquote>
| |
| − | <p>The structural integrity check verifies if internal filesystem objects or
| |
| − | data structures satisfy the constraints, point to the right objects or are
| |
| − | correctly connected together.</p>
| |
| − | <p>There are several cross checks that can detect wrong reference counts of shared
| |
| − | extents, backrefrences, missing extents of inodes, directory and inode
| |
| − | connectivity etc.</p>
| |
| − | <p>The amount of memory required can be high, depending on the size of the
| |
| − | filesystem, smililarly the run time.</p>
| |
| − | ==SAFE OR ADVISORY OPTIONS==
| |
| − |
| |
| − | <dl>
| |
| − | <dt>
| |
| − | -b|--backup
| |
| − | <dd>
| |
| − | <p>
| |
| − | use the first valid set of backup roots stored in the superblock
| |
| − | </p>
| |
| − | <p>This can be combined with <em>--super</em> if some of the superblocks are damaged.</p>
| |
| − |
| |
| − | <dt>
| |
| − | --check-data-csum
| |
| − | <dd>
| |
| − | <p>
| |
| − | verify checksums of data blocks
| |
| − | </p>
| |
| − | <p>This expects that the filesystem is otherwise
| |
| − | OK, so this is basically and offline <em>scrub</em> but does not repair data from
| |
| − | spare coipes.</p>
| |
| − |
| |
| − | <dt>
| |
| − | --chunk-root <em><bytenr></em>
| |
| − | <dd>
| |
| − | <p>
| |
| − | use the given offset <em>bytenr</em> for the chunk tree root
| |
| − | </p>
| |
| − |
| |
| − | <dt>
| |
| − | -E|--subvol-extents <em><subvolid></em>
| |
| − | <dd>
| |
| − | <p>
| |
| − | show extent state for the given subvolume
| |
| − | </p>
| |
| − |
| |
| − | <dt>
| |
| − | -p|--progress
| |
| − | <dd>
| |
| − | <p>
| |
| − | indicate progress at various checking phases
| |
| − | </p>
| |
| − |
| |
| − | <dt>
| |
| − | --qgroup-report
| |
| − | <dd>
| |
| − | <p>
| |
| − | verify qgroup accounting and compare against filesystem accounting
| |
| − | </p>
| |
| − |
| |
| − | <dt>
| |
| − | -r|--tree-root <em><bytenr></em>
| |
| − | <dd>
| |
| − | <p>
| |
| − | use the given offset <em>bytenr</em> for the tree root
| |
| − | </p>
| |
| − |
| |
| − | <dt>
| |
| − | --readonly
| |
| − | <dd>
| |
| − | <p>
| |
| − | (default)
| |
| − | run in read-only mode, this option exists to calm potential panic when users
| |
| − | are going to run the checker
| |
| − | </p>
| |
| − |
| |
| − | <dt>
| |
| − | -s|--super <em><superblock></em>
| |
| − | <dd>
| |
| − | <p>
| |
| − | use 'superblock’th superblock copy, valid values are 0, 1 or 2 if the
| |
| − | respective superblock offset is within the device size
| |
| − | </p>
| |
| − | <p>This can be used to use a different starting point if some of the primary
| |
| − | superblock is damaged.</p>
| |
| − |
| |
| − | </dl>
| |
| − | ==DANGEROUS OPTIONS==
| |
| − |
| |
| − | <dl>
| |
| − | <dt>
| |
| − | --repair
| |
| − | <dd>
| |
| − | <p>
| |
| − | enable the repair mode and attempt to fix problems where possible
| |
| − | </p>
| |
| − |
| |
| − | <dt>
| |
| − | --init-csum-tree
| |
| − | <dd>
| |
| − | <p>
| |
| − | create a new checksum tree and recalculate checksums in all files
| |
| − | </p>
| |
| − | <blockquote><b>Note:</b>
| |
| − | Do not blindly use this option to fix checksum mismatch problems.</blockquote>
| |
| − |
| |
| − | <dt>
| |
| − | --init-extent-tree
| |
| − | <dd>
| |
| − | <p>
| |
| − | build the extent tree from scratch
| |
| − | </p>
| |
| − | <blockquote><b>Note:</b>
| |
| − | Do not use unless you know what you’re doing.</blockquote>
| |
| − |
| |
| − | <dt>
| |
| − | --mode=MODE
| |
| − | <dd>
| |
| − | <p>
| |
| − | select mode of operation regarding memory and IO
| |
| − | </p>
| |
| − | <p>The <em>MODE</em> can be one of <em>original</em> and <em>lowmem</em>. The original mode is mostly
| |
| − | unoptimized regarding memory consumpption and can lead to out-of-memory
| |
| − | conditions on large filesystems. The possible workaround is to export the block
| |
| − | device over network to a machine with enough memory. The low memory mode is
| |
| − | supposed to address the memory consumption, at the cost of increased IO when it
| |
| − | needs to re-read blocks when needed. This may increase run time.</p>
| |
| − |
| |
| − | </dl>
| |
| − | <blockquote><b>Note:</b>
| |
| − | <em>lowmem</em> mode does not work with <em>--repair</em> yet, and is still considered
| |
| − | experimental.</blockquote>
| |
| − | ==EXIT STATUS==
| |
| − |
| |
| − | <p><b>btrfs check</b> returns a zero exit status if it succeeds. Non zero is
| |
| − | returned in case of failure.</p>
| |
| − | ==AVAILABILITY==
| |
| − |
| |
| − | <p><b>btrfs</b> is part of btrfs-progs.
| |
| − | Please refer to the btrfs wiki http://btrfs.wiki.kernel.org for
| |
| − | further details.</p>
| |
| − | ==SEE ALSO==
| |
| − |
| |
| − | <p>[[Manpage/mkfs.btrfs|mkfs.btrfs(8)]],
| |
| − | [[Manpage/btrfs-scrub|btrfs-scrub(8)]],
| |
| − | [[Manpage/btrfs-rescue|btrfs-rescue(8)]]</p>
| |
| − | [[Category:Manpage]]
| |
