Mysql 5.6主从搭建

mysql设置主从的重要性和必要性不必多说，下面开始详细说明如何搭建主从。

1、主服务器上创建一个用于复制的账户。

mysql> GRANT REPLICATION SLAVE ON *.* TO 'repl'@'192.168.47.3' IDENTIFILED BY '1234';
mysql> flush privileges;

2、主服务器参数修改

[root@localhost ~]# vi /usr/local/mysql5.6/etc/my.cnf
修改如下内容
server-id = 1
log-bin=mysql-bin

3、主服务器备份数据，并传输

mysql>  flush tables with read lock;
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000036 |     3252 |              |                  |                   |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)

[root@localhost ~]# /usr/local/mysql5.6/bin/./mysqldump -uroot -p --all-databases | gzip > bak.sql.gz
[root@localhost ~]# scp bak.sql.gz root@192.168.47.3:~/

mysql> unlock tables;

4、从服务器恢复数据

[root@localhost bin]# gunzip bak.sql.gz
[root@localhost bin]# mysql -uroot -p
mysql> source ~/bak.sql;

5、修改从服务器配置

[root@localhost bin]# vi /etc/my.cnf
添加如下内容
server-id = 2
重启服务器
[root@localhost ~]# service mysql restar

6、从服务器设置主从配置

mysql> CHANGE MASTER TO
-> MASTER_HOST='192.168.47.5',
-> MASTER_USER='repl',   
-> MASTER_PASSWORD='1234',
-> MASTER_LOG_FILE='mysql-bin.000036',
-> MASTER_PORT=3307,
-> MASTER_LOG_POS=3252;

MASTER_HOST指的是主服务器的IP地址，
MASTER_USER指的是复制的账户
MASTER_PASSWORD指的是账户的密码
MASTER_PORT指的是主服务器端口
MASTER_LOG_FILE指的是bin-log的文件
MASTER_LOG_POS指的是日志文件位

7、从服务器启动slave线程

mysql> start slave;
mysql> show processlist;
+----+-------------+-----------+------+---------+------+-----------------------------------------------------------------------------+------------------+-----------+---------------+
| Id | User        | Host      | db   | Command | Time | State                                                                       | Info             | Rows_sent | Rows_examined |
+----+-------------+-----------+------+---------+------+-----------------------------------------------------------------------------+------------------+-----------+---------------+
|  1 | system user |           | NULL | Connect |  714 | Slave has read all relay log; waiting for the slave I/O thread to update it | NULL             |         0 |             0 |
|  2 | system user |           | NULL | Connect |  714 | Waiting for master to send event                                            | NULL             |         0 |             0 |
|  4 | root        | localhost | NULL | Query   |    0 | init                                                                        | show processlist |         0 |             0 |
+----+-------------+-----------+------+---------+------+-----------------------------------------------------------------------------+------------------+-----------+---------------+
3 rows in set (0.08 sec)

这已经表明主从已经搭建成功。

8、测试

主服务器中

mysql> use warehouse
Database changed
mysql> select * from aaa;
+------+------+
| a    | b    |
+------+------+
|    1 |    2 |
|    1 |    2 |
|    1 |    2 |
|    2 |    3 |
|    2 |    7 |
+------+------+
5 rows in set (0.06 sec)

从服务器中

mysql>  use warehouse;
Database changed
mysql> select * from aaa;
+------+------+
| a    | b    |
+------+------+
|    1 |    2 |
|    1 |    2 |
|    1 |    2 |
|    2 |    3 |
|    2 |    7 |
+------+------+
5 rows in set (0.21 sec)

主服务器中

mysql> insert into aaa values (5,7),(56,21);
Query OK, 2 rows affected (0.21 sec)
Records: 2  Duplicates: 0  Warnings: 0

mysql> select * from aaa;
+------+------+
| a    | b    |
+------+------+
|    1 |    2 |
|    1 |    2 |
|    1 |    2 |
|    2 |    3 |
|    2 |    7 |
|    5 |    7 |
|   56 |   21 |
+------+------+
7 rows in set (0.00 sec)

从服务器中

mysql> select * from aaa;
+------+------+
| a    | b    |
+------+------+
|    1 |    2 |
|    1 |    2 |
|    1 |    2 |
|    2 |    3 |
|    2 |    7 |
|    5 |    7 |
|   56 |   21 |
+------+------+
7 rows in set (0.00 sec)

9、管理主从

查看从服务器状态

mysql> show slave status G;
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.47.5
                  Master_User: repl
                  Master_Port: 3307
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000036
          Read_Master_Log_Pos: 3484
               Relay_Log_File: localhost-relay-bin.000002
                Relay_Log_Pos: 283
        Relay_Master_Log_File: mysql-bin.000036
             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: 3484
              Relay_Log_Space: 460
              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
Master_SSL_Verify_Server_Cert: No
                Last_IO_Errno: 0
                Last_IO_Error: 
               Last_SQL_Errno: 0
               Last_SQL_Error: 
  Replicate_Ignore_Server_Ids: 
             Master_Server_Id: 1
                  Master_UUID: 86d34969-fa5d-11e6-b372-000c29c88c3f
             Master_Info_File: /usr/local/mysql/data/master.info
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: Slave has read all relay log; waiting for the slave I/O thread to update it
           Master_Retry_Count: 86400
                  Master_Bind: 
      Last_IO_Error_Timestamp: 
     Last_SQL_Error_Timestamp: 
               Master_SSL_Crl: 
           Master_SSL_Crlpath: 
           Retrieved_Gtid_Set: 
            Executed_Gtid_Set: 
                Auto_Position: 0
1 row in set (0.00 sec)

关心的两个信息是Slave_IO_Running和Slave_SQL_Running是否是YES。Slave_IO_Running是从主服务器读取BINLOG日志，并写入到从服务器的中继日志中；Slave_SQL_Running负责读取和执行中继日志信息。

注意：如果需要从服务器禁止写入操作，则需要更改参数read-only，使从服务器非root账户只能读数据。