WARNING: mismatch_cnt is not 0 on /dev/md0

[knifebunny]

You may get a message from logwatch

WARNING: mismatch_cnt is not 0 on /dev/md0

This means that there is a mismatch of the synchronisation of the blocks between
your two (or more) drives.

Firstly, check that the array is healthy:

cat /proc/mdstat

then perform:

repair >/sys/block/md0/md/sync_action

this will attempt to repair the poorly synchronised blocks on md0

you can check if the synchronisation is finished by

cat /proc/mdstat

after the repair is completed, you can check if synchronisation had been
successful with:

check >/sys/block/md0/md/sync_action


Apparently it is fairly common to have this happen on /boot and swap partitions, however if you are particularly concerned it might be worthwhile using smartctl to
do a test of the integrity of the drive.

smartctl --test long /dev/sda

you can inspect the progress on the smartctl via this command

smartctl -a /dev/md2