环境
A: 192.168.0.1 B: 192.168.0.2
其中A上已经有数据库在服务，需要在B上搭建一个备库，并且和A实现双向同步。
设置
授权复制用户
即分别在A，B上增加一个用户让彼此访问
A: grant replication slave,file on *.* to 'backup'@'192.168.0.2' identified by '123456'; B: grant replication slave,file on *.* to 'backup'@'192.168.0.1' identified by '123456';
检测通过backup这个用户能够访问彼此的MySQL。
配置文件设置
B:
[mysqld] # 省略... # replication settings # A 192.168.0.1 # B 192.168.0.2 server-id=2 log-bin=/home/mysql/log/mysql-bin # 因为是双向，自动增加的id会有冲突，把步长改为2 初始设为2 auto_increment_increment=2 auto_increment_offset=2 # master设置 master-host=192.168.0.1 master-user=backup master-pass=123456 master-port=3306 master-connect-retry=30 # 设置需要复制的库 replicate-do-db=your_db1 replicate-do-db=your_db2 # 省略...
A:
[mysqld] # 省略... # replication settings # A 192.168.0.1 # B 192.168.0.2 server-id=1 log-bin=/home/mysql/log/mysql-bin # 因为是双向，自动增加的id会有冲突，把步长改为2 初始设为1 auto_increment_increment=2 auto_increment_offset=1 # master设置 master-host=192.168.0.2 master-user=backup master-pass=123456 master-port=3306 master-connect-retry=30 # 设置需要复制的库 replicate-do-db=your_db1 replicate-do-db=your_db2 # 省略...
同步现有数据
停止A数据库的操作，把A中的数据用mysqldump或者直接拷贝文件的方法复制到B，确保B正常。
设置并检查同步
启动A和B上的的MySQL
A:
mysql> show master status; +------------------+----------+--------------+------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | +------------------+----------+--------------+------------------+ | mysql-bin.000004 | 8937501 | | | +------------------+----------+--------------+------------------+ 1 row in set (0.00 sec)
B:
mysql> show master status; +------------------+----------+--------------+------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | +------------------+----------+--------------+------------------+ | mysql-bin.000019 | 597 | | | +------------------+----------+--------------+------------------+ 1 row in set (0.00 sec)
A:
mysql> show slave status\G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.0.2
Master_User: backup
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000019
Read_Master_Log_Pos: 597
Relay_Log_File: mysqld-relay-bin.000005
Relay_Log_Pos: 429
Relay_Master_Log_File: mysql-bin.000019
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB: your_db1,your_db2
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: 597
Relay_Log_Space: 429
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: 0
1 row in set (0.00 sec)
B:
mysql> show slave status\G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.0.1
Master_User: backup
Master_Port: 3306
Connect_Retry: 30
Master_Log_File: mysql-bin.000004
Read_Master_Log_Pos: 9914005
Relay_Log_File: mysqld-relay-bin.000008
Relay_Log_Pos: 9914142
Relay_Master_Log_File: mysql-bin.000004
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB: your_db1,your_db2
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: 9914005
Relay_Log_Space: 9914142
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: 0
1 row in set (0.00 sec)
需要特别注意的是这两行：
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
必须都是Yes，否则同步不成功。
分别在A和B上做操作，看同步是否生效；
复制不成功的解决方法
一开始我设置从A复制到B时出现了错误
Slave_IO_Running: No
Slave_SQL_Running: Yes
mysqld.log里面：
121217 17:43:39 [ERROR] Error reading packet from server: error reading log entry ( server_errno=1236) 121217 17:43:39 [ERROR] Got fatal error 1236: 'error reading log entry' from master when reading data from binary log
这时我用 CHANGE MASTER命令重新指定master：
A:
mysql> show master status; +------------------+----------+--------------+------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | +------------------+----------+--------------+------------------+ | mysql-bin.000003 | 98 | | | +------------------+----------+--------------+------------------+ 1 row in set (0.00 sec)
记住上面的File和Position数值
mysql> slave stop; mysql> change master to master_host='192.168.0.1',master_user='backup',master_password='123456', master_log_file='mysql-bin.000003',master_log_pos=98; mysql> slave start;
此时检查B上的slave status, 发现已经OK：
Slave_IO_Running: Yes
Slave_SQL_Running: Yes