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

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.
           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 running.

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>

System Manager's Manual       Device Mapper Tools                thin_check(8)