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

cache_check - validates cache metadata on a device or file.

cache_check [options] {device|file}

cache_check checks cache metadata created by the device-mapper cache target on a device or file.

This tool cannot be run on live metadata.

-h, --help
Print help and exit.
-V, --version
Output version information and exit.
-q, --quiet
Suppress output messages, return only exit code.
Only check the superblock.
Skip checking of the policy hint values metadata.
Skip checking of the discard bits in the metadata.
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 cache_repair run
is needed to fix any issues. After cache_repair succeeded, you may run
cache_check again.

Analyses and repairs cache metadata on logical volume /dev/vg/metadata:
$ cache_check /dev/vg/metadata
The device may not be actively used by the target when running.

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

cache_dump(8), cache_repair(8), cache_restore(8)

Joe Thornber <>, Heinz Mauelshagen <>
Device Mapper Tools System Manager's Manual