Mysql主主同步失败后的恢复

基础信息

主库:

• 数据库2 10.126.4.2
• 数据库3 10.126.4.3

1. 停止数据库3对外服务

防止同步过程中服务通过数据库3写入数据

$ firewall-cmd --remove-port=3306/tcp $ firewall-cmd --add-rich-rule="rule f amily="ipv4" source address="10.126.4.2" port protocol="tcp" port="3306" accept" $ firewall-cmd --reload 

2. 备份主库

$ mysqldump -uroot -p --single-transaction --master-data=2 --no-autocommit -A >alldatas-190708.sql 

记住 MASTER_LOG_FILE 和 MASTER_LOG_POS

$ head -n 30 alldatas-190708.sql 

-- CHANGE MASTER TO MASTER_LOG_FILE='mysql-bin.000016', MASTER_LOG_POS=801595396; 

3. 切断数据库2、3的同步

两台主机分别执行

mysql>change master to master_host='' mysql>stop slave; mysql>reset slave; 

4. 清空数据库3

清空数据文件

$ rm /var/lib/mysql $ mv /db/mysql /db/mysql-190708 $ mkdir /db/mysql $ ln -s /db/mysql /var/lib/mysql chown mysql:mysql /var/lib/mysql chown -h mysql:mysql /var/lib/mysql 

初始化

mysqld --initialize --user=mysql grep password /var/log/mysqld.log 

重置 master 和 slave

mysql> reset master; mysql> show master status\G mysql> stop slave; mysql> reset slave; mysql> show slave status\G 

 File: mysql-bin.000001 Position: 154 Binlog_Do_DB: Binlog_Ignore_DB: Executed_Gtid_Set: 1 row in set (0.00 sec) ERROR: No query specified 

5. 导入主库信息，重新指向主库

$ mysql -uroot -p < alldatas.sql 

mysql > change master to -> master_host='10.126.4.2', -> master_user='repl', -> master_password='********', -> master_log_file='binlog.???', -> master_log_pos=???; mysql > start slave; mysql > show slave status\G 

6. 数据库2配置主库信息

查询数据库3的 master_log_file 和 master_log_pos

10.126.4.3

show master status; 

10.126.4.2

mysql > change master to -> master_host='10.126.4.3', -> master_user='repl', -> master_password='********', -> master_log_file='binlog.???', -> master_log_pos=???; mysql > show slave status\G 

7. 放开数据库3对外服务

$ firewall-cmd --reload 

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