Mysql主从复制

 1、环境说明

MasterIP：192.168.12.150

SlaveIP: 192.168.12.151

2 、yum安装mysql

yum install mysql-server -y

3、配置Master的Mysql，在mysqld模块下添加如下两行；

[root@bogon ~]# vi /etc/my.cnf
[mysqld]
server-id = 1
log-bin=mysql-bin 日志路径及文件名

 4、在Master数据库上设置同步用户，并给用户授权；

[root@bogon ~]# mysql -u root
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 6
Server version: 5.0.95-log Source distribution

Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> grant replication slave on *.* to 'rep'@'192.168.12.%' identified by '123456';
Query OK, 0 rows affected (0.00 sec)

5、主库锁表，停止数据更新。(锁表的作用是，防止备份数据库的时候，数据库的写入，备份完数据库之后，查看主库的状态)

mysql> flush tables with read lock;

6、查看主库的状态；

mysql> show master status;
+------------------+----------+--------------+------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000003 |      234 |              |                  |
+------------------+----------+--------------+------------------+
1 row in set (0.00 sec)

mysql>

将上面的日志名mysql-bin.000003和偏移量234记录下来，从库将已它作为同步点，它之前的数据我们通过mysqldump、mysql命令导出，导入到从数据库，它之后的数据我们将进行同步。

7、数据库解锁

mysql> unlock tables;

8、修改Slave数据库的配置文件,只需要添加server-id = 2 就ok，并重启mysqld

[root@localhost ~]# vi /etc/my.cnf
[mysqld]
server-id = 2
datadir=/var/lib/mysq
[root@localhost ~]# service mysqld restart Stopping mysqld:  [  OK  ]

9、在从库中开始手动同步数据库。

mysql> change master to master_host='192.168.12.150',master_user='rep',master_password='123456',master_log_file='mysql-bin.000003' ,master_log_pos=234;
Query OK, 0 rows affected (0.01 sec)

mysql> start slave;    启动从数据库
Query OK, 0 rows affected (0.00 sec)

mysql> show slave status \G; 查看状态
*************************** 1. row ***************************
             Slave_IO_State: Connecting to master
                Master_Host: 192.168.12.150
                Master_User: rep
                Master_Port: 3306
              Connect_Retry: 60
            Master_Log_File: mysql-bin.000003
        Read_Master_Log_Pos: 234
             Relay_Log_File: mysqld-relay-bin.000001
              Relay_Log_Pos: 98
      Relay_Master_Log_File: mysql-bin.000003
           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: 234
            Relay_Log_Space: 98
            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
1 row in set (0.00 sec)

ERROR:
No query specified

mysql>

标红的两个线程显示状态为yes，说明同步成功。

10 、测试主从数据库是否同步成功

主库上创建数据库test，并查看是否创建成功检查从库是否自动创建数据test

mysql> create database test;
Query OK, 1 row affected (0.00 sec)

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| test               |
+--------------------+
3 rows in set (0.00 sec)

检查从库是否自动创建数据test

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| test               |
+--------------------+
3 rows in set (0.00 sec)

mysql> show slave status \G;
*************************** 1. row ***************************
             Slave_IO_State: Waiting for master to send event
                Master_Host: 192.168.12.150
                Master_User: rep
                Master_Port: 3306
              Connect_Retry: 60
            Master_Log_File: mysql-bin.000004
        Read_Master_Log_Pos: 777
             Relay_Log_File: mysqld-relay-bin.004413
              Relay_Log_Pos: 235
      Relay_Master_Log_File: mysql-bin.000004
           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: 777
            Relay_Log_Space: 235
            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)

ERROR:
No query specified

mysql>

主库上删除数据库test，，并查看主库的状态

mysql> drop database test;
Query OK, 0 rows affected (0.00 sec)

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
+--------------------+
2 rows in set (0.00 sec)

检查从库是否自动删除数据库test，

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
+--------------------+
2 rows in set (0.00 sec)

mysql> show slave status \G;
*************************** 1. row ***************************
             Slave_IO_State: Waiting for master to send event
                Master_Host: 192.168.12.150
                Master_User: rep
                Master_Port: 3306
              Connect_Retry: 60
            Master_Log_File: mysql-bin.000004
        Read_Master_Log_Pos: 858
             Relay_Log_File: mysqld-relay-bin.011065
              Relay_Log_Pos: 235
      Relay_Master_Log_File: mysql-bin.000004
           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: 858
            Relay_Log_Space: 235
            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)

ERROR:
No query specified

自此达到主从同步成功。

总结：主从同步最最要的的得到主库的查看主库的状态；得到File和Position的值mysql-bin.000003 ，234 ，从库同步的时候会用到。

mysql> show master status;
+------------------+----------+--------------+------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000003 |      234 |              |                  |
+------------------+----------+--------------+------------------+
1 row in set (0.00 sec)

mysql>

 因为我们同步的时候是以它作为同步点的，它之后的数据我们将自动同步，它之前的数据我们将通过mysqldump的命令导入的，所以在备份主库的时候我们一定要锁表，（flush tables with read lock; ） 这样数据库就不能写了，File和Position的值mysql-bin.000003 ，234 ，也就不会变化 这样我们就保证了数据同步的完整性。 备份完数据库之后我们就可以通过 unlock tables; 

命令解锁了。然后我们通过在主库上授权的用户在从库上开始第一次手动同步，yihou