1thin_check(8)               System Manager's Manual              thin_check(8)
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NAME

6       thin_check - validates thin provisioning metadata on a device or file
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SYNOPSIS

9       thin_check [options] {device|file}
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DESCRIPTION

13       thin_check checks thin provisioning metadata created by the device-map‐
14       per thin provisioning target on a device or file.
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16       The tool cannot be run on live metadata unless the  --metadata-snapshot
17       option is used.
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OPTIONS

20       -q, --quiet
21              Suppress output messages, return only exit code.
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23       -h, --help
24              Print help and exit.
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26       -V, --version
27              Output version information and exit.
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29       --super-block-only
30              Only check the superblock.
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32       --skip-mappings
33              Skip  checking  of  the block mappings which make up the bulk of
34              the metadata.
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36       --ignore-non-fatal-errors
37              Will only return a non-zero exit code if it finds a fatal error.
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39           An example of a nonfatal error is an incorrect data block reference count
40           causing a block to be considered allocated when it in fact isn't.  Ignoring
41           errors for a long time is not advised, you really should be using
42           thin_repair to fix them.
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45       --clear-needs-check-flag
46              Clears the 'needs_check' flag in the superblock.
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48           The kernel may set a flag to force the pool to be checked before it's next
49           activated.  Set this switch to clear the flag if the check is successful.
50           If the metadata check failed, the flag is not cleared and a thin_repair run
51           is needed to fix any issues. After thin_repair succeeded, you may run
52           thin_check again.
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55       --metadata-snapshot, -m
56              Check the metadata snapshot.
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58           This will check the devices tree and mappings in a metadata snapshot.
59           The snap does not contain space maps, so these will not be checked.  This
60           may be used on live metadata.
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63       --auto-repair
64              Automatically repair any trivial issues found with the metadata.
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66           Currently only fixes metadata leaks.
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69       --override-mapping-root <block>
70              Specify a mapping root to use.
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72           Don't use this.  This overrides what's specified in the superblock.  Only
73           use this if you really understand the metadata format and are trying to
74           recover damaged metadata.
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EXAMPLE

78       Analyses thin provisioning metadata on logical volume /dev/vg/metadata:
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80           $ thin_check /dev/vg/metadata
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82       The device must not be actively used by the target when running.
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DIAGNOSTICS

85       thin_check returns an exit code of 0 for success or 1 for error.
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SEE ALSO

88       thin_dump(8), thin_repair(8), thin_restore(8), thin_rmap(8), thin_meta‐
89       data_size(8)
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AUTHOR

92       Joe Thornber <ejt@redhat.com>, Heinz Mauelshagen <heinzm@redhat.com>
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96System Manager's Manual       Device Mapper Tools                thin_check(8)
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