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

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>