# Text automatically generated by txt2man

     NAME
          thin_check - validates thin provisioning metadata on a
          device or file

     SYNOPSIS
          thin_check [options] {device|file}

     DESCRIPTION
          thin_check checks thin provisioning metadata created by the
          device-mapper thin provisioning target on a device or file.

          The tool cannot be run on live metadata unless the --
          metadata-snapshot option is used.

     OPTIONS
          -q, --quiet
               Suppress output messages, return only exit code.

          -h, --help
               Print help and exit.

          -V, --version
               Output version information and exit.

          --super-block-only
               Only check the superblock.

          --skip-mappings
               Skip checking of the block mappings which make up the
               bulk of the metadata.

          --ignore-non-fatal-errors
               Will only return a non-zero exit code if it finds a
               fatal error.

              An example of a nonfatal error is an incorrect data block reference count
              causing a block to be considered allocated when it in fact isn't.  Ignoring
              errors for a long time is not advised, you really should be using
              thin_repair to fix them.

          --clear-needs-check-flag
               Clears the 'needs_check' flag in the superblock.

              The kernel may set a flag to force the pool to be checked before it's next
              activated.  Set this switch to clear the flag if the check is successful.
              If the metadata check failed, the flag is not cleared and a thin_repair run
              is needed to fix any issues. After thin_repair succeeded, you may run
              thin_check again.

          --metadata-snapshot, -m
               Check the metadata snapshot.

              This will check the devices tree and mappings in a metadata snapshot.

     Page 1               System Manager's Manual    (printed 5/23/22)

     thin_check(8)         (Device Mapper Tools)         thin_check(8)

              The snap does not contain space maps, so these will not be checked.  This
              may be used on live metadata.

          --auto-repair
               Automatically repair any trivial issues found with the
               metadata.

              Currently only fixes metadata leaks.

          --override-mapping-root <block>
               Specify a mapping root to use.

              Don't use this.  This overrides what's specified in the superblock.  Only
              use this if you really understand the metadata format and are trying to
              recover damaged metadata.

     EXAMPLE
          Analyses thin provisioning metadata on logical volume
          /dev/vg/metadata:

              $ thin_check /dev/vg/metadata

          The device must not be actively used by the target when run-
          ning.

     DIAGNOSTICS
          thin_check returns an exit code of 0 for success or 1 for
          error.

     SEE ALSO
          thin_dump(8), thin_repair(8), thin_restore(8), thin_rmap(8),
          thin_metadata_size(8)

     AUTHOR
          Joe Thornber <ejt@redhat.com>, Heinz Mauelshagen
          <heinzm@redhat.com>

     Page 2               System Manager's Manual    (printed 5/23/22)