checking state of RAID (for automated notifications)

I would like to have RAID status monitored by nagios.

This sounds like a simple script, but I'm not sure what approach is correct.

Considering, that the "health" status of /proc/mdstat looks like this:

# cat /proc/mdstat
Personalities : [raid1] [raid10]
md2 : active raid10 sda2[4] sdd2[3] sdc2[2] sdb2[1]
      779264640 blocks super 1.0 64K chunks 2 near-copies [4/4] [UUUU]

md1 : active raid1 sdd1[1] sdc1[0]

      1076224 blocks [2/2] [UU]

md0 : active raid1 sdb1[1] sda1[0]

      1076224 blocks [2/2] [UU]

unused devices: <none>

What my script should be checking?

Does the number of "U" (8 for this host) letters indicate that RAID is healthy? Or should I count "in_sync" in "cat /sys/block/md*/md/rd*/state"? Perhaps the two approaches are the same, though.

What's the best way to determine that the RAID is running fine?

Tomasz Chmielewski
http://wpkg.org

<berlin> % rpm -qf /usr/lib/nagios/plugins/contrib/check_linux_raid.pl nagios-plugins-1.4.1-1.2.fc4.rf

It is built in to my nagios plugins package at least, and works great.

-Mike

All right, I didn't see it.

I was thinking of monitoring remote servers; I wrote something very simple.
It checks how many "U" letters there are in /proc/mdstat, and compares it to $DEVICES number we have.

First, run this one on a remote machine, via cron:

#!/bin/bash

# This script prints the status of RAID device on this machine

# how many RAID devices/partitions do we have here?
DEVICES=8

# no need to change anything below...

RUNNING=$(cat /proc/mdstat | tr -cd "U" | wc -c)

if [ "$DEVICES" == "$RUNNING" ] ; then

echo "RAID status OK" > /tmp/raid-status.txt

else

echo "RAID broken" > /tmp/raid-status.txt

fi

And then poll the results from the nagios server (let's call it "check_raid" nagios plugin):

#!/bin/bash

# checks state of software RAID

STATUS=$(ssh -l checkuser -i ~nagios/.ssh/checkuser.rsa $1 "cat /tmp/raid-status.txt")

if [ "$STATUS" == "RAID status OK" ] ; then
echo $STATUS
exit 0
else
echo $STATUS
exit 2
fi

Tomasz Chmielewski
http://wpkg.org