MySQL主从配置

一、准备

1、主从数据库的版本号最好一直（因为官方推荐这样，最主要还是怕版本不一致带来的不兼容问题;）

2、主从数据库内数据保持一致，若不一致可将从数据库的数据备份备份出来。在将从数据库的数据全都删除，并将主库的数据全部导入进去

 

主数据库：192.168.122.135

从数据库：192.168.122.136

 

二、操作

　　主数据库操作

1、开启binlog

【mysqld】

log-bin=mysql-bin
server-id=1#主从的server-id不能一样

 2、启动主库

systemctl start mysql  #用来创建同步的用户

 3、登陆数据库

mysql -uroot -p

 4、创建一个测试库、表

>create database game;
>use game;
>show tables;
>create table LOL( id int AUTO_INCREMENT PRIMARY KEY, name char(20), age int);
>insert into LOL(name,age) values('JS',12),('XYR',23);

 5、在主库上创建供slave远程连接的用户并授权(用户LM。slave库ip。密码)

>create user 'LM'@'192.168.122.136' identified by 'Www.1.com';

 6、授予复制权限

>grant replication slave on *.* to 'LM'@'192.168.122.136';

 7、刷新

>flush privileges;

 8、锁表，禁止写入，当前窗口不能退出，这时候开启另一个终端继续操作

>flush table with read lock;

 9、新窗口操作，查看master状态，记录二进制文件名和位置

>show master status;
+------------------+----------+--------------+------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000003 |     1042 |              |                  |
+------------------+----------+--------------+------------------+

 10、把当前数据导出

# mysqldump -u root -p --all-databases > alldb.sql

 11、解锁查看binlog日志位置，如果没变化证明锁定成功，从库将从这个binlog日志开始恢复

>unlock tables;

>show master status;
+------------------+----------+--------------+------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000003 |     1042 |              |                  |
+------------------+----------+--------------+------------------+

 　　从库操作

1、导入数据库

# mysql -u root -p < alldb.sql 

 2、修改配置文件

server-id=2  #设置server-id，必须唯一

3、重启mysql，配置同步（需要主服务器主机名，登陆凭证，二进制文件的名称和位置）

change master to master_host='192.168.122.135',
    -> master_user='LM',
    -> master_password='Www.1.com',
    -> master_log_file='mysql-bin.000003',
    -> master_log_pos=1024;

 4、启动slave

>start slave;

 5、查看slave状态

>show slave status\G;
如果
Slava_IO_Running:YES
Slave_SQL_Runing:YES 
即可

 

 三、错误解决

　　Slave_IO_Running: No

由于主服务器异外重启, 导致从报错, 错误如下:
show slave status错误:
mysql> show slave status\G
Master_Log_File: mysql-bin.000288
Read_Master_Log_Pos: 627806304
Relay_Log_File: mysql-relay-bin.000990
Relay_Log_Pos: 627806457
Relay_Master_Log_File: mysql-bin.000288
Slave_IO_Running: No
Slave_SQL_Running: Yes
Exec_Master_Log_Pos: 627806304
Relay_Log_Space: 627806663

 　　查看日志

tail /data/mysql/mysql-error.log
111010 17:35:49 [ERROR] Error reading packet from server: Client requested master
 to start replication from impossible position ( server_errno=1236)
111010 17:35:49 [ERROR] Slave I/O: Got fatal error 1236 from master when reading data
from binary log: 'Client requested master to start replication from impossible
position', Error_code: 1236
111010 17:35:49 [Note] Slave I/O thread exiting, read up to log 'mysql-bin.000288',
position 627806304

 　　解决方法

错误依旧, 接下来登陆到主服务器查看binlog日志.
先按照错误点的标记去主服务器日志中查找:

[root@db1 ~]# mysqlbinlog --start-position=627655136 /data/mysql/binlog/mysql-bin.000288
/*!40019 SET @@session.max_insert_delayed_threads=0*/;
/*!50003 SET @OLD_COMPLETION_TYPE=@@COMPLETION_TYPE,COMPLETION_TYPE=0*/;
DELIMITER /*!*/;
# at 4
#111010 13:31:19 server id 4 end_log_pos 106 Start: binlog v 4, server v 5.1.45-log
created 111010 13:31:19
# Warning: this binlog is either in use or was not closed properly.
BINLOG '
F1aTTg8EAAAAZgAAAGoAAAABAAQANS4xLjQ1LWxvZwAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAEzgNAAgAEgAEBAQEEgAAUwAEGggAAAAICAgC
'/*!*/;
DELIMITER ;
# End of log file
ROLLBACK /* added by mysqlbinlog */;
/*!50003 SET COMPLETION_TYPE=@OLD_COMPLETION_TYPE*/;
没有看到这个位置.

[root@db1 ~]# mysqlbinlog /data/mysql/binlog/mysql-bin.000288 > test.txt

less text.txt
看最后一部分
# at 627625495
#111010 16:35:46 server id 1 end_log_pos 627625631 Query thread_id=45613333
exec_time=32758 error_code=0
SET TIMESTAMP=1318289746/*!*/;
delete from freeshipping_bef_update where part='AR-4006WLM' and code=''
/*!*/;
# at 627625631
#111010 16:35:46 server id 1 end_log_pos 627625751 Query thread_id=45613333
exec_time=32758 error_code=0
SET TIMESTAMP=1318289746/*!*/;
delete from shippingFee_special where part='AR-4006WLM'
/*!*/;
DELIMITER ;
# End of log file
ROLLBACK /* added by mysqlbinlog */;
/*!50003 SET COMPLETION_TYPE=@OLD_COMPLETION_TYPE*/;
找到最接近错误标记627655136的一个position是627625631.

再回到slave机器上change master, 将postion指向这个位置.

mysql> stop slave;
Query OK, 0 rows affected (0.00 sec)

mysql> change master to master_log_file='mysql-bin.000288',master_log_pos=627625631;
Query OK, 0 rows affected (0.06 sec)

mysql> start slave;
Query OK, 0 rows affected (0.00 sec)
再次查看

mysql> show slave status\G
*************************** 1. row ***************************
Slave_IO_State: Queueing master event to the relay log
Master_Host: 192.168.21.105
Master_User: rep
Master_Port: 3306
Connect_Retry: 10
Master_Log_File: mysql-bin.000289
Read_Master_Log_Pos: 25433767
Relay_Log_File: mysql-relay-bin.000003
Relay_Log_Pos: 630
Relay_Master_Log_File: mysql-bin.000289
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
主从同步正常了, 同样的方法修复其它slave机器.