Nagios 监控服务器剩余内存

tdfd

Linux系统内存机制:在linux中有这么一种思想，内存不用白不用，因此它尽可能的cache和buffer一些数据，以方便下次使用。但实际上这些内存也是可以立刻拿来使用的。所以 空闲内存=free+buffers+cached   

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#!/bin/bash   USAGE="`basename $0` [-w|--warning]<percent free> [-c|--critical]<percent free>"   THRESHOLD_USAGE="WARNING threshold must be greater than CRITICAL: `basename $0` $*"   calc=/tmp/memcalc   percent_free=/tmp/mempercent   critical=""   warning=""   STATE_OK=0   STATE_WARNING=1   STATE_CRITICAL=2   STATE_UNKNOWN=3   # print usage   if [ $# -lt 4 ]; then       echo ""       echo "Wrong Syntax: `basename $0` $*"       echo ""       echo "Usage: $USAGE"       echo ""       exit 0   fi   # read input   while [ $# -gt 0 ]   do       case "$1" in           -w|--warning)               shift               warning=$1               ;;           -c|--critical)               shift               critical=$1               ;;       esac       shift   done           # verify input   if [[ $warning -eq $critical || $warning -lt $critical ]]; then       echo ""       echo "$THRESHOLD_USAGE"       echo ""       echo "Usage: $USAGE"       echo ""       exit 0   fi   # Total memory available   total=`free -m | head -2 |tail -1 |gawk '{print $2}'`   # Total memory used   used=`free -m | head -3 |tail -1 |awk '{print $3}'`   # Calc total minus used   free=`free -m | head -3 |tail -1 |awk '{print $4}'`   # normal values   #echo "$total"MB total   #echo "$used"MB used   #echo "$free"MB free   # make it into % percent free = ((free mem / total mem) * 100)   echo "5" > $calc # decimal accuracy   echo "k" >> $calc # commit   echo "100" >> $calc # multiply   echo "$free" >> $calc # division integer   echo "$total" >> $calc # division integer   echo "/" >> $calc # division sign   echo "*" >> $calc # multiplication sign   echo "p" >> $calc # print   percent=`/usr/bin/dc $calc|/bin/sed 's/^\./0./'|/usr/bin/tr "." " "|/usr/bin/gawk {'print $1'}`   #percent1=`/usr/bin/dc $calc`   #echo "$percent1"   if [[ "$percent" -le  $critical ]];  then       echo "CRITICAL - $free MB ($percent%) Free Memory"       exit 2   fi   if [[ "$percent" -le  $warning ]]; then       echo "WARNING - $free MB ($percent%) Free Memory"       exit 1   fi   if [[ "$percent" -gt  $warning ]]; then       echo "OK - $free MB ($percent%) Free Memory"       exit 0   fi