xfs_metadump(8) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | DIAGNOSTICS | NOTES | SEE ALSO | BUGS | COLOPHON

xfs_metadump(8)          System Manager's Manual         xfs_metadump(8)

NAME         top

       xfs_metadump - copy XFS filesystem metadata to a file

SYNOPSIS         top

       xfs_metadump [ -aefFgow ] [ -m max_extents ] [ -l logdev ] source
       target
       xfs_metadump -V

DESCRIPTION         top

       xfs_metadump is a debugging tool that copies the metadata from an
       XFS filesystem to a file.  The source argument must be the
       pathname of the device or file containing the XFS filesystem and
       the target argument specifies the destination file name.  If
       target is -, then the output is sent to stdout. This allows the
       output to be redirected to another program such as a compression
       application.

       xfs_metadump may only be used to copy unmounted filesystems, or
       read-only mounted filesystems.

       xfs_metadump does not alter the source filesystem in any way. The
       target image is a contiguous (non-sparse) file containing all the
       filesystem's metadata and indexes to where the blocks were copied
       from.

       By default, xfs_metadump obfuscates most file (regular file,
       directory and symbolic link) names and extended attribute names
       to allow the dumps to be sent without revealing confidential
       information. Extended attribute values are zeroed and no data is
       copied. The only exceptions are file or attribute names that are
       4 or less characters in length. Also file names that span extents
       (this can only occur with the mkfs.xfs(8) options where -n size >
       -b size) are not obfuscated. Names between 5 and 8 characters in
       length inclusively are partially obfuscated.

       xfs_metadump cannot obfuscate metadata in the filesystem log.
       Log recovery of an obfuscated metadump image may expose clear-
       text metadata and/or cause filesystem corruption in the restored
       image.  It is recommended that the source filesystem first be
       mounted and unmounted, if possible, to ensure that the log is
       clean.  A subsequent invocation of xfs_metadump will capture a
       clean log and obfuscate all metadata correctly.

       If a metadump must be produced from a filesystem with a dirty
       log, it is recommended that obfuscation be turned off with -o
       option, if metadata such as filenames is not considered
       sensitive.  If obfuscation is required on a metadump with a dirty
       log, please inform the recipient of the metadump image about this
       situation.

       xfs_metadump should not be used for any purposes other than for
       debugging and reporting filesystem problems. The most common
       usage scenario for this tool is when xfs_repair(8) fails to
       repair a filesystem and a metadump image can be sent for
       analysis.

       The file generated by xfs_metadump can be restored to filesystem
       image (minus the data) using the xfs_mdrestore(8) tool.

OPTIONS         top

       -a     Copies entire metadata blocks.  Normally, xfs_metadump
              will zero any stale bytes interspersed with in-use
              metadata.  Use this option to copy full metadata blocks,
              to provide more debugging information for a corrupted
              filesystem.  Note that the extra data will be
              unobfuscated.

       -e     Stops the dump on a read error. Normally, it will ignore
              read errors and copy all the metadata that is accessible.

       -f     Specifies that the filesystem image to be processed is
              stored in a regular file (see the mkfs.xfs -d file
              option). This can also happen if an image copy of a
              filesystem has been made into an ordinary file with
              xfs_copy(8).

       -F     Specifies that we want to continue even if the superblock
              magic is not correct.  If the source is truly not an XFS
              filesystem, the resulting image will be useless, and
              xfs_metadump may crash.

       -g     Shows dump progress. This is sent to stdout if the target
              is a file or to stderr if the target is stdout.

       -l logdev
              For filesystems which use an external log, this specifies
              the device where the external log resides. The external
              log is not copied, only internal logs are copied.

       -m     Set the maximum size of an allowed metadata extent.
              Extremely large metadata extents are likely to be corrupt,
              and will be skipped if they exceed this value.  The
              default size is 2097151 blocks.

       -o     Disables obfuscation of file names and extended
              attributes.

       -w     Prints warnings of inconsistent metadata encountered to
              stderr. Bad metadata is still copied.

       -V     Prints the version number and exits.

DIAGNOSTICS         top

       xfs_metadump returns an exit code of 0 if all readable metadata
       is successfully copied or 1 if a write error occurs or a read
       error occurs and the -e option used.

NOTES         top

       As xfs_metadump copies metadata only, it does not matter if the
       source filesystem has a realtime section or not. If the
       filesystem has an external log, it is not copied. Internal logs
       are copied and any outstanding log transactions are not
       obfuscated if they contain names.

       xfs_metadump is a shell wrapper around the xfs_db(8) metadump
       command.

SEE ALSO         top

       xfs_repair(8), xfs_mdrestore(8), xfs_freeze(8), xfs_db(8),
       xfs_copy(8), xfs(5)

BUGS         top

       Email bug reports to linux-xfs@vger.kernel.org.

COLOPHON         top

       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 linux-xfs@vger.kernel.org.  This page was obtained
       from the project's upstream Git repository
       ⟨https://git.kernel.org/pub/scm/fs/xfs/xfsprogs-dev.git⟩ on
       2020-12-18.  (At that time, the date of the most recent commit
       that was found in the repository was 2020-12-11.)  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 man-pages@man7.org

                                                         xfs_metadump(8)

Pages that refer to this page: xfs_db(8)xfs_mdrestore(8)xfs_repair(8)