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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | OPTIMIZATIONS | REPAIRS | EXIT CODE | CAVEATS | SEE ALSO | COLOPHON |
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xfs_scrub(8) System Manager's Manual xfs_scrub(8)
xfs_scrub - check and repair the contents of a mounted XFS
filesystem
xfs_scrub [ -abCemnTvx ] mount-point
xfs_scrub -V
xfs_scrub attempts to check and repair all metadata in a mounted
XFS filesystem.
WARNING! This program is EXPERIMENTAL, which means that its
behavior and interface could change at any time!
xfs_scrub asks the kernel to scrub all metadata objects in the
filesystem. Metadata records are scanned for obviously bad
values and then cross-referenced against other metadata. The
goal is to establish a reasonable confidence about the
consistency of the overall filesystem by examining the
consistency of individual metadata records against the other
metadata in the filesystem. Damaged metadata can be rebuilt from
other metadata if there exists redundant data structures which
are intact.
Filesystem corruption and optimization opportunities will be
logged to the standard error stream. Enabling verbose mode will
increase the amount of status information sent to the output.
If the kernel scrub reports that metadata needs repairs or
optimizations and the user does not pass -n on the command line,
this program will ask the kernel to make the repairs and to
perform the optimizations. See the sections about optimizations
and repairs for a list of optimizations and repairs known to this
program. The kernel may not support repairing or optimizing the
filesystem. If this is the case, the filesystem must be
unmounted and xfs_repair(8) run on the filesystem to fix the
problems.
-a errors
Abort if more than this many errors are found on the
filesystem.
-b Run in background mode. If the option is specified once,
only run a single scrubbing thread at a time. If given
more than once, an artificial delay of 100us is added to
each scrub call to reduce CPU overhead even further.
-C fd This option causes xfs_scrub to write progress information
to the specified file description so that the progress of
the filesystem check can be monitored. If the file
description is a tty, a fancy progress bar is rendered.
Otherwise, a simple numeric status dump compatible with
the fsck -C format is output.
-e Specifies what happens when errors are detected. If
shutdown is given, the filesystem will be taken offline if
errors are found. If continue is given, no action is
taken if errors are found; this is the default behavior.
-k Do not call TRIM on the free space.
-m file
Search this file for mounted filesystems instead of
/etc/mtab.
-n Only check filesystem metadata. Do not repair or optimize
anything.
-T Print timing and memory usage information for each phase.
-v Enable verbose mode, which prints periodic status updates.
-V Prints the version number and exits.
-x Read all file data extents to look for disk errors.
xfs_scrub will issue O_DIRECT reads to the block device
directly. If the block device is a SCSI disk, it will
instead issue READ VERIFY commands directly to the disk.
If media errors are found, the error report will include
the disk offset, in bytes. If the media errors affect a
file, the report will also include the inode number and
file offset, in bytes. These actions will confirm that
all file data blocks can be read from storage.
Optimizations supported by this program include, but are not
limited to:
• Instructing the underlying storage to discard unused extents
via the TRIM ioctl.
• Updating secondary superblocks to match the primary superblock.
• Turning off shared block write checks for files that no longer
share blocks.
Repairs are performed by calling into the kernel. This limits
the scope of repair activities to rebuilding primary data
structures from secondary data structures, or secondary
structures from primary structures. The existence of secondary
data structures may require features that can only be turned on
from mkfs.xfs(8). If errors cannot be repaired, the filesystem
must be unmounted and xfs_repair(8) run. Repairs supported by
the kernel include, but are not limited to:
• Reconstructing extent allocation data.
• Rebuilding free space information.
• Rebuilding inode indexes.
• Fixing minor corruptions of inode records.
• Recalculating reference count information.
• Reconstructing reverse mapping data from primary extent
allocation data.
• Scheduling a quotacheck for the next mount.
If corrupt metadata is successfully repaired, this program will
log that a repair has succeeded instead of a corruption report.
The exit code returned by xfs_scrub is the sum of the following
conditions:
0 - No errors
1 - File system errors left uncorrected
2 - File system optimizations possible
4 - Operational error
8 - Usage or syntax error
xfs_scrub is an immature utility! Do not run this program unless
you have backups of your data! This program takes advantage of
in-kernel scrubbing to verify a given data structure with locks
held and can keep the filesystem busy for a long time. The
kernel must be new enough to support the SCRUB_METADATA ioctl.
If errors are found and cannot be repaired, the filesystem must
be unmounted and repaired.
xfs_repair(8).
This page is part of the xfsprogs (utilities for XFS filesystems)
project. Information about the project can be found at
⟨http://xfs.org/⟩. If you have a bug report for this manual page,
send it to [email protected]. This page was obtained
from the project's upstream Git repository
⟨https://git.kernel.org/pub/scm/fs/xfs/xfsprogs-dev.git⟩ on
2024-06-14. (At that time, the date of the most recent commit
that was found in the repository was 2024-05-17.) If you
discover any rendering problems in this HTML version of the page,
or you believe there is a better or more up-to-date source for
the page, or you have corrections or improvements to the
information in this COLOPHON (which is not part of the original
manual page), send a mail to [email protected]
xfs_scrub(8)
Pages that refer to this page: ioctl_xfs_scrub_metadata(2), xfs_scrub_all(8)
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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