如何实现实时监控数据库主从同步的状态

1. 需要先明白数据库主从同步正常的标准是来查看两个线程Slave_IO和Slave_SQL两个线程的工作状态；

2. 下面的问题就是如何去实时监测这两个线程的状态?

下面我们用脚本的方式来实现监控操作：

代码如下：

#!/bin/bash
#Check MySQL Slave's Runnning Status
#Crontab time 00:10

MYSQLPORT=`netstat -na|grep "LISTEN"|grep "3306"|awk -F[:" "]+ '{print $5}'`
MYSQLIP=`ifconfig eth0|grep "inet addr" | awk -F[:" "]+ '{print $4}'`
STATUS=$(/usr/bin/mysql -uroot -p11111 -S /var/lib/mysql/mysql.sock -e "show slave status\G" | grep -i "running")
IO_env=`echo $STATUS | grep IO | awk  ' {print $2}'`
SQL_env=`echo $STATUS | grep SQL | awk  '{print $2}'`
DATA=`date +"%y-%m-%d %H:%M:%S"`

function checkMysqlStatus(){
    if [ "$MYSQLPORT" == "3306" ]
    then
        /usr/bin/mysql -uroot -p11111 --connect_timeout=5 -e "show databases;" &>/dev/null 2>&1
        if [ $? -ne 0 ]
        then
            echo "Server: $MYSQLIP mysql is down, please try to restart mysql by manual!" > /var/log/mysqlerr
            mail -s "WARN! server: $MYSQLIP  mysql is down." admin@yourdomain.com < /var/log/mysqlerr
        else
            echo "mysql is running..."
        fi
    else
        mail -s "WARN!Server: $MYSQLIP mysql is down." admin@yourdomain.com
    fi
}

checkMysqlStatus

if [ "$IO_env" = "Yes" -a "$SQL_env" = "Yes" ]
then
  echo "MySQL Slave is running!"
else
  echo "####### $DATA #########">> /data/mysql/mysql_slave_status.log
  echo "MySQL Slave is not running!" >>    /data/mysql/mysql_slave_status.log
  echo "MySQL Slave is not running!" | mail -s "WARN! $MYSQLIP MySQL Slave is not running." admin@yourdomain.com
fi

建议每十分钟运行一次
*/10 * * * * root /bin/sh /root/mysql_slave_status.sh

原理：

1）监控MYSQL的运行状态；
2）Slave机器的IO和SQL状态都必须为YES，缺一不可；

注意，请结合自身的实际环境使用。