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+# check_mdstat.sh
+This script reads from `/proc/mdstat` to get the status of a RAID devices.
+
+Other than [check_md_raid](https://exchange.icinga.com/exchange/check_md_raid) and [check_md_raid updated](https://exchange.icinga.com/jasem/check_md_raid updated/) not all RAIDs are checked simulataneously, but only one specific. This gives the possibility to query some "performance" data and later add more granular checks.
+
+## Arguments
+* --raid | -r: Name of the RAID, e.g. `md0`
+* --input | -i: Input file. Defaults to /proc/mdstat
+* --debug | -d: More debugging output, cannot be used with icinga2
+
+## Results
+* CRITICAL: if any device failed
+* CRITICAL: if the state of the RAID is not active/started
+* WARNING: when recoverying/resyncing
+* CRITICAL: if the number of active devices is smaller than the number of active devices.
+
+## Known issues
+Probably I did not get things right with spare devices.
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