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mysql数据库主从库配置之主从切换

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Jun 13, 2016 am 08:39 AM

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mysql数据库主从库配置之主从切换

MySQL：主从复制(Replication)搭建介绍了 MySQL 主从配置过程，这篇介绍手工主从切换过程。

一环境信息
主库 192.168.1.60/3306 主机名 db1
备库 192.168.1.61/3306 主机名 db2
备注：主从节点 mysql 安装略，Replication 安装略。

二主从切换
--主，备节点都要创建 Replication 用户。如果无，参考下面创建。
create user 'rep1'@'%' identified by 'rep1abcd1243d'; GRANT REPLICATION SLAVE ON *.* TO 'rep1'@'%'; 

--查询从库状态
root@localhost:francs>show slave status\G 

--查询主库状态
root@localhost:francs>show slave hosts; +-----------+-------------------+------+-----------+--------------------------------------+ | Server_id | Host | Port | Master_id | Slave_UUID | +-----------+-------------------+------+-----------+--------------------------------------+ | 2 | 192.168.2.38(db2) | 3306 | 1 | ad397a06-7c56-11e4-b2fb-000c29dcb3b5 | +-----------+-------------------+------+-----------+--------------------------------------+ 1 row in set (0.00 sec) 

--从库: 停止 IO_THREAD 线程
root@localhost:francs>stop slave IO_THREAD; root@localhost:francs>show slave status\G *************************** 1. row *************************** Slave_IO_State: Master_Host: 192.168.2.37 Master_User: rep1 Master_Port: 3306 Connect_Retry: 60 Master_Log_File: bin-log.000001 Read_Master_Log_Pos: 362 Relay_Log_File: db2-relay-bin.000002 Relay_Log_Pos: 523 Relay_Master_Log_File: bin-log.000001 Slave_IO_Running: No Slave_SQL_Running: Yes Replicate_Do_DB: Replicate_Ignore_DB: Replicate_Do_Table: Replicate_Ignore_Table: Replicate_Wild_Do_Table: Replicate_Wild_Ignore_Table: Last_Errno: 0 Last_Error: Skip_Counter: 0 Exec_Master_Log_Pos: 362 Relay_Log_Space: 694 Until_Condition: None Until_Log_File: Until_Log_Pos: 0 Master_SSL_Allowed: No Master_SSL_CA_File: Master_SSL_CA_Path: Master_SSL_Cert: Master_SSL_Cipher: Master_SSL_Key: Seconds_Behind_Master: NULL Master_SSL_Verify_Server_Cert: No Last_IO_Errno: 0 Last_IO_Error: Last_SQL_Errno: 0 Last_SQL_Error: Replicate_Ignore_Server_Ids: Master_Server_Id: 1 Master_UUID: 0c130d47-22bb-11e4-aaaa-000c2986ac80 Master_Info_File: mysql.slave_master_info SQL_Delay: 0 SQL_Remaining_Delay: NULL Slave_SQL_Running_State: Slave has read all relay log; waiting for the slave I/O thread to update it Master_Retry_Count: 86400 Master_Bind: Last_IO_Error_Timestamp: Last_SQL_Error_Timestamp: Master_SSL_Crl: Master_SSL_Crlpath: Retrieved_Gtid_Set: Executed_Gtid_Set: Auto_Position: 0 1 row in set (0.00 sec) 

--激活从库(从库上操作)
root@localhost:francs>stop slave; root@localhost:francs>reset master; root@localhost:francs>reset slave all; root@localhost:francs>show binary logs; +----------------+-----------+ | Log_name | File_size | +----------------+-----------+ | bin-log.000001 | 120 | +----------------+-----------+ 1 row in set (0.00 sec) 
备注：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。

--将原来主库变为从库
mysql> CHANGE MASTER TO MASTER_HOST='192.168.1.61', MASTER_PORT=3306, MASTER_USER='rep1', MASTER_PASSWORD='rep1abcd1243d', MASTER_LOG_FILE='bin-log.000001', MASTER_LOG_POS=120; root@localhost:francs>start slave; root@localhost:francs>show slave status\G 
备注：这步执行之后，发现 db1 日志文件报了以下错误，提示 db1 连接不上 db2。

--db1 日志报错
2015-03-02 14:24:14 26198 [ERROR] Slave I/O: error connecting to master 'rep1@192.168.1.61:3306' - retry-time: 60 retries: 8, Error_code: 1045 

--解决过程
--连接测试 [mysql@db1 ~]$ mysql -h 192.168.1.60 -P 3306 -urep1 备注：居然不需要密码能直接能连上。 --测试匿名用户 [mysql@db1 ~]$ mysql -h 192.168.1.60 -P 3306 -urep2 备注：依然不需要密码。 --原因分析 root@localhost:francs>select Host,User,Password from mysql.user where User=''; +-----------+------+----------+ | Host | User | Password | +-----------+------+----------+ | localhost | | | | db1 | | | +-----------+------+----------+ 备注: 原来 db2 节点上存在 User 为空的的两行，表示匿名用户可以连接数据库，删除这两行，之后 flush privileges; --再连接测试 [mysql@db1 ~]$ mysql -h 192.168.1.60 -P 3306 -urep1 备注：这次连接需要密码了。之后再次观看 db1 同步日志，不再报错。 

三数据验证
主从切换后db2 为主节点， db1 为备节点，在 db2 节点上插入一条数据测试同步是否正常。

--db2 上执行
root@localhost:francs>insert into test_sr(id) values(30); Query OK, 1 row affected (0.03 sec) root@localhost:francs>select * from test_sr order by id desc limit 1; +------+---------------------+ | id | create_time | +------+---------------------+ | 30 | 2015-03-02 15:19:53 | +------+---------------------+ 1 row in set (0.00 sec) 

--db1 上验证
root@localhost:francs>select * from test_sr order by id desc limit 1; +------+---------------------+ | id | create_time | +------+---------------------+ | 30 | 2015-03-02 15:19:53 | +------+---------------------+ 1 row in set (0.00 sec) 
备注：数据同步正常，以上是对 MySQL 主备切换的初次了解，后续再补充。