MYSQL主从切换，mysql主从
1修改配置文件
read-only=1（主库）
#read-only=1（备库）
2、查看主备库状态
show slave status \G
show master status\G
3、操作备库
STOP SLAVEIO_THREAD;
SHOW PROCESSLIST;
看到Has read all relay log
show slave status \G
STOP SLAVE;
RESET MASTER;
RESET SLAVE;
grant replication slave on *.* to'testuser'@'10.45.172.40' identified by 'test123';
show master status\G
如执行reset master;后
遇到ERROR 1186 (HY000): Binlog closed, cannot RESET MASTER的问题
处理方法：
修改vim /etc/my.cnf
加上log-bin=mysql-bin
重启mysqld服务。
4、操作主库
show master status\G
RESET MASTER;
RESET SLAVE;
CHANGE MASTER TO
MASTER_HOST='10.45.172.37',
MASTER_USER='testuser',
MASTER_PASSWORD='test123',
MASTER_PORT=3306,
MASTER_LOG_FILE='mysql-bin.000001',
MASTER_LOG_POS=98,
MASTER_CONNECT_RETRY=60;
5、重启新主从库，开启slave进程
Start slave
SHOW PROCESSLIST;
show slave status \G