Tommey @live

*/5 * * * * bash /path/to/file/check_memory_usage.sh &> /dev/null

#!/bin/bash
#############################################################################
# Check memory usage script                                                 #
# This script will check for the highest virtual and physical memory usage. #
# If they exceed a given limit then a report will be sent to a given email. #
# Written by: Tommey <http://coderprofile.com/coder/Tommey>  @ 2009.02.27   #
#############################################################################
 
# Config - set mail sending command, limits (in kB) , report tmp file
mail_cmd="mail monitor@email-address.com -s MemUsageCheck"
limit_vsz=20000  # in kB
limit_rss=10000  # in kB
limit_warning=90  # in %
limit_critical=95 # in %
limit_report_lines=10
report_file="/tmp/check_mem_usage_report"
memget_file="/tmp/check_mem_usage_get"
 
# Init
echo "---------------------------"
echo "Check memory usage (script)"
echo "---------------------------"
send_email=0
 
echo "Memory Usage Statistics (MB)" > $report_file
free -m -t > $memget_file
get_memory=`cat $memget_file | head -2 | tail -1 | awk '{print " Memory: "$2"\t"$3"\t"$4"\t"$7}'` 
get_swap=`cat $memget_file | head -4 | tail -1 |  awk '{print " Swap:   "$2"\t"$3"\t"$4}'`
get_total=`cat $memget_file | tail -1 | awk '{print " Total:  "$2"\t"$3"\t"$4}'`
get_max=`cat $memget_file | tail -1 | awk '{print $2}'`
get_total_used=`cat $memget_file | tail -1 | awk '{print $3}'`
get_cached=`cat $memget_file | head -2 | tail -1 | awk '{print $7}'`
get_real_used=`printf "%.0lf" $(echo "scale=4; $get_total_used-$get_cached" | bc)`
get_limit_warning=`printf "%.0lf" $(echo "scale=4; $get_max*$limit_warning/100" | bc)`
get_limit_critical=`printf "%.0lf" $(echo "scale=4; $get_max*$limit_critical/100" | bc)`
get_usage_percent=`printf "%0.2lf" $(echo "scale=4; $get_real_used/$get_max*100" | bc)`
get_physical=`cat $memget_file | head -2 | tail -1 | awk '{print $3" "$2" "$7}'` 
get_virtual=`cat $memget_file | head -4 | tail -1 |  awk '{print $3" "$2}'`
 
echo -n "Checking total memory usage..."
if [ $get_limit_warning -lt $get_real_used ] && [ $get_real_used -lt $get_limit_critical ] 
then
    echo "WARNING, usage is above $limit_warning% -> $get_usage_percent%"
    echo " " >> $report_file
    echo " WARNING - Total memory usage is above $limit_warning%!" >> $report_file
    echo " " >> $report_file
    let send_email+=1
elif [ $get_limit_critical -lt $get_real_used ] 
then
    echo "CRITICAL, usage is above $limit_critical% -> $get_usage_percent%"
    echo " " >> $report_file
    echo " CRITICAL - Total memory usage is above $limit_critical%!" >> $report_file
    echo " " >> $report_file
    let send_email+=1
else
    echo "OK, usage: $get_usage_percent% - $get_real_used MB / $get_max MB"
    printf " - Physical: %3d MB / %3d MB, cached: %d MB\n" $get_physical
    printf " - Virtual:  %3d MB / %3d MB\n" $get_virtual
fi
echo "        Total   Used    Free   Cached" >> $report_file
echo "$get_memory" >> $report_file
echo "$get_swap" >> $report_file
echo "$get_total" >> $report_file
echo " " >> $report_file
 
# Check virtual memory usage
max_vsz=`ps axo vsz --sort -vsz | head -2 | tail -1`
report_vsz=`ps axo pid,pcpu,vsz,rss,comm,cmd --sort -vsz | head -$(($limit_report_lines+1))`
 
echo -n "Checking virtual memory usage..."
if [ $max_vsz -gt $limit_vsz ] 
then
    echo "EXCEEDED with size: $(($max_vsz-$limit_vsz)) kB, limit: $limit_vsz kB"
    echo "Top $limit_report_lines processes by Virtual Memory Usage (limit: $limit_vsz kB)" >> $report_file
    echo "$report_vsz" >> $report_file
    echo " " >> $report_file
    let send_email+=1
else
    echo "OK - max: $max_vsz kB, limit: $limit_vsz kB"
fi
 
# Check physical memory usage
max_rss=`ps axo rss --sort -rss | head -2 | tail -1`
report_rss=`ps axo pid,pcpu,vsz,rss,comm,cmd --sort -rss | head -$(($limit_report_lines+1))`
 
echo -n "Checking physical memory usage..."
if [ $max_rss -gt $limit_rss ] 
then
    echo "EXCEEDED with size: $(($max_rss-$limit_rss)) kB, limit: $limit_rss kB"
    echo "Top $limit_report_lines processes by Physical Memory Usage (limit: $limit_rss kB)" >> $report_file
    echo "$report_rss" >> $report_file
    let send_email+=1
else
    echo "OK - max: $max_rss kB, limit: $limit_rss kB"
fi
 
# Check if report created and send
if [ $send_email -gt 0 ] 
then
    echo "$send_email check(s) FAILED!"
    echo -n "Sending notify email..."
    $mail_cmd < $report_file
    echo "DONE."
else
    echo "All checks PASSED!"
fi
 
rm -f $report_file