Mysql搭建主从复制

主库:192.168.1.1

从库:192.168.1.2

数据文件存放位置:/data/datafile

待同步数据库:repdb

一.设置MASTER

1.修改my.cnf

# vi /etc/my.cnf

server-id = 1

log-bin

binlog-ignore-db=mysql

2.赋予SLAVE权限帐号,允许用户在SLAVE上LOAD TABLE和LOAD DATA

mysql>GRANT FILE,SELECT,REPLICATION SLAVE ON *.* TO user_rep@192.168.1.2 IDENTIFIED BY 'rep123';

3.锁主库表

mysql>FLUSH TABLES WITH READ LOCK;

4.显示主库信息

记录File和Position,从库设置将会用到

mysql>SHOW MASTER STATUS G;

*************************** 1. row ***************************

File: mysql-bin.000030

Position: 391156558

Binlog_Do_DB:

Binlog_Ignore_DB:

5.另开一个终端,打包主库

/data/datafile/ # tar cvf repdb.tar repdb

二.设置SLAVE

1.传输拿到主库包,解包

/data/datafile/ # scp 192.168.1.1:/data/datafile/repdb.tar .

/data/datafile # tar xvf repdb.tar

2.解锁主库表

mysql>UNLOCK TABLES;

3.查看修改repdb文件夹权限

/data/datafile # chown mysql:mysql repdb -R

4.修改my.cnf

# vi /etc/my.cnf

#slave

server-id=2

master-host=192.168.1.1

master-user=user_rep

master-password=rep123

master-port=3306

replicate-do-db=repdb

5.验证连接MASTER

# mysql -h192.168.1.1 -uuser_rep -prep123

mysql>show grants;

+------------------------------------------------------------------------------+
| Grants for user_rep@192.168.1.2 |
+------------------------------------------------------------------------------+
| GRANT SELECT, FILE, REPLICATION SLAVE ON *.* TO user_rep@192.168.1.2 IDENTIFIED BY 
PASSWORD '*9FF2C222F44C7BBA5CC7E3BE8573AA4E1776278C' |
+------------------------------------------------------------------------------+

6.本地登录mysql

设置连接MASTER MASTER_LOG_FILE为主库的File

MASTER_LOG_POS为主库的Position

mysql>CHANGE MASTER TO

MASTER_HOST='192.168.1.1',

MASTER_USER='user_rep',

MASTER_PASSWORD='rep123',

MASTER_LOG_FILE='mysql-bin.000030',

MASTER_LOG_POS=391156558;

7.启动SLAVE服务

mysql>slave start;

8.本地登录mysql,查看SLAVE状态

mysql>SHOW SLAVE STATUS G;

*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.1.1
Master_User: user_rep
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: binlog.000001
Read_Master_Log_Pos: 98
Relay_Log_File: relay.000003
Relay_Log_Pos: 232
Relay_Master_Log_File: binlog.000001
Slave_IO_Running: Yes
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: 98
Relay_Log_Space: 232
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

Slave_IO_Running 和Slave_SQL_Running 两列的值都为 "Yes",表明 Slave 的 I/O 和 SQL 线程都在正常运行.

到此主从库搭建成功. 

从库SLAVE启动问题

由于一些错误操作导致CHANGE MASTER和SLAVE服务无法启动,系统报错如下:

Could not initialize master info structure; more error messages can be found in the MySQL error log.

无法初始化master info结构;MySQL错误日志记录了更详细的错误信息.

解决方法:

1.查看MySQL错误日志,查看原因.

如:同步的上一个Position是多少.

很多情况下无法启动服务是由于mysql识别的同步始终停留在上一个Position上.

2.查看master.info和relay-log.info

master.info 记录MASTER相关信息

14
mysql-bin.000030
391156558
192.168.1.1
user_rep
rep123
3306
60
0

relay-log.info 记录当前同步日志信息

235
mysql-bin.000030
391156558

3.停止myslq服务,删除master.info和relay-log.info

# service mysql stop

/data/datafile/ # rm master.info

/data/datafile/ # rm relay-log.info

4.启动mysql服务

# service mysql start

5.重新CHANGE MASTER,重新启动SLAVE服务.

问题应该就可以解决了.