mysql mon 的一個監控指令碼，監控heartbeat

#!/bin/bash
trap 'echo  PROGRAM INTERRUPTED; exit 1'  INT
username=username
password=password
n=0
echo >mysqlmon.log
while true;
do
   if /usr/local/mysql/bin/mysql  -u$username -p$password -e "use test"   >&/dev/null;
      then
        echo `date +"%Y-%m-%d  %H:%M:%S"`  mysqld is alive!  >>mysqlmon.log
        n=0
      else
        echo  `date +"%Y-%m-%d  %H:%M:%S"`  mysqld  cannot be  connected!  >>mysqlmon.log
        n=$[n + 1]
        if [ $n -eq 3 ] ; then
           service heartbeat stop
           echo  `date +"%Y-%m-%d  %H:%M:%S"`  mysqld  switched to backup!  >>mysqlmon.log
           break
        fi
      fi
  sleep 10
done