MySQL主从切换

参考上一篇博客 MySQL主从同步http://blog.csdn.net/juded/article/details/54600294

从库状态确认

确保从库执行完了relay log更新后，停止IO_THREAD线程。

mysql> show slave status\G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
          ...........
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes
          ...........
      Slave_SQL_Running_State: Slave has read all relay log; waiting for the slave I/O
          ...........

停止从库IO_THREAD线程

mysql> stop slave io_thread;
Query OK, 0 rows affected (0.06 sec)

从库上升为主库

mysql> grant replication slave on *.* to 'repl'@'%' identified by 'repl';

mysql> stop slave;
Query OK, 0 rows affected (0.01 sec)

mysql> reset master;
Query OK, 0 rows affected (0.06 sec)

mysql> reset slave all;

mysql>show slave status\G
Empty set (0.00 sec)

mysql>show master status;
+------------------+----------+--------------+------------------+
| File       | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin-2.000001 |    639| db1,db2   |     |
+------------------+----------+--------------+------------------+

reset slave all 命令会删除从库的 replication 参数，之后 show slave status\G 的信息返回为空。

主库上升为从库

mysql> change master to
    -> master_host='192.168.2.94',
    -> master_port=3306,
    -> master_user='repl',
    -> master_password='repl',
    -> master_log_file='mysql-bin-2.000001',
    -> master_log_pos=639;
Query OK, 0 rows affected, 2 warnings (0.34 sec)

mysql> start slave;
Query OK, 0 rows affected (0.04 sec)