Check mem (by Nestor@Toronto)

This is a great script that various people have improved. I've been using a forked version on github for some years. We recently improved it to use '/proc/meminfo' output so it its less brittle to changes in 'free' output. So it works with almost all Linux releases/versions. Small improvements to the chart also.

https://github.com/whereisaaron/linux-check-mem-nagios-plugin

Hi,

Here is a modification for more accurate results on CentOS/RHEL 6.x. This changes the memUsed_m variable to use a custom calculation instead of just using the Used number from free -m.

This is similar to what the other reviewer did for 7.x systems. It uses the number from memTotal_m and then subtracts memFree_m, memBuffer_m, and memCache_m to come up with memUsed_m. You need to comment the original memUsed_m line then add a line after memCache_m as shown:


memTotal_m=`echo "$FreeM" |grep Mem |awk '{print $2}'`

# Comment This Line #memUsed_m=`echo "$FreeM" |grep Mem |awk '{print $3}'`

memFree_m=`echo "$FreeM" |grep Mem |awk '{print $4}'`
memBuffer_m=`echo "$FreeM" |grep Mem |awk '{print $6}'`
memCache_m=`echo "$FreeM" |grep Mem |awk '{print $7}'`

#Add the following line:

memUsed_m=$(($memTotal_m-$memFree_m-$memBuffer_m-$memCache_m))

memUsedPrc=`echo $((($memUsed_m*100)/$memTotal_m))||cut -d. -f1`


Thanks for the great plugin!

Centos 7 Free command output changed a bit, plus I would count cached memory as free.

#!/bin/bash

if [ "$1" = "-w" ] && [ "$2" -gt "0" ] && [ "$3" = "-c" ] && [ "$4" -gt "0" ]; then
FreeM=`free -m`
memTotal_m=`echo "$FreeM" |grep Mem |awk '{print $2}'`
memUsed_m=`echo "$FreeM" |grep Mem |awk '{print $3}'`
memFree_m=`echo "$FreeM" |grep Mem |awk '{print $4}'`
memBuffer_cache_m=`echo "$FreeM" |grep Mem |awk '{print $6}'`
memAvailable_m=`echo "$FreeM" |grep Mem |awk '{print $7}'`

memUsed_m=$(($memTotal_m-$memFree_m-$memBuffer_cache_m))

memUsedPrc=`echo $((($memUsed_m*100)/$memTotal_m))||cut -d. -f1`
if [ "$memUsedPrc" -ge "$4" ]; then
echo "Memory: CRITICAL Total: $memTotal_m MB - Used: $memUsed_m MB - $memUsedPrc% used!|TOTAL=$memTotal_m;;;; USED=$memUsed_m;;;; BUFFER/CACHE=$memBuffer_cache_m;;;; AVAILABLE=$memAvailable_m;;;;"
exit 2
elif [ "$memUsedPrc" -ge "$2" ]; then
echo "Memory: WARNING Total: $memTotal_m MB - Used: $memUsed_m MB - $memUsedPrc% used!|TOTAL=$memTotal_m;;;; USED=$memUsed_m;;;; BUFFER/CACHE=$memBuffer_cache_m;;;; AVAILABLE=$memAvailable_m;;;;"
exit 1
else
echo "Memory: OK Total: $memTotal_m MB - Used: $memUsed_m MB - $memUsedPrc% used|TOTAL=$memTotal_m;;;; USED=$memUsed_m;;;; BUFFER/CACHE=$memBuffer_cache_m;;;; AVAILABLE=$memAvailable_m;;;;"
exit 0
fi
else # If inputs are not as expected, print help.
sName="`echo $0|awk -F '/' '{print $NF}'`"
echo -e "\n\n\t\t### $sName Version 2.1###\n"
echo -e "# Usage:\t$sName -w -c "
echo -e "\t\t= warnlevel and critlevel is percentage value without %\n"
echo "# EXAMPLE:\t/usr/lib64/nagios/plugins/$sName -w 80 -c 90"
echo -e "\nCopyright (C) 2012 Lukasz Gogolin (lukasz.gogolin@gmail.com), improved by Nestor 2015\n\n"
exit
fi