MySQL复制之初体验

配置主库

主库必须启用二进制日志并有唯一的server ID，设置后需要重启mysql服务生效。主从数据传输同步是根据binlog实现的，如果未启用binlog，复制是不可能的。复制组内每个服务器都必须有一个唯一的server ID，此ID用来标识各个服务器，且为1-2的32次方之间的整数,默认为0。

[mysqld]
log-bin=master_info
server-id=1
innodb_flush_log_at_trx_commit=1
sync_binlog=1

配置从库

从库也必须有唯一的server ID，不能省略，否则拒绝连接。

[mysqld]
server-id=2

创建复制用户

帐号需可被从库访问，并具有REPLICATION SLAVE权限，也可不必单独为复制创建帐号。

[master]
mysql> GRANT REPLICATION SLAVE ON *.* TO 'repluser'@'192.168.90.129' IDENTIFIED BY 'mypass';
Query OK, 0 rows affected (0.02 sec)

获取主库二进制日志执行位置并同步数据

配置复制需要指定从库开始执行主库的二进制日志的起始执行位置，因此当从库同步主库现有数据时，需要停止在主库上执行更新语句，然后获得主库的当前二进制日志座标并转储数据。如果主库继续执行更新操作，可能导致主从数据不一致。

获取主库二进制日志座标的方式：

• 主库执行FLUSH TABLES WITH READ LOCK 语句:

mysql> FLUSH TABLES WITH READ LOCK;

该语句刷新所有表及块写入语句，对于InnoDB表还会阻塞Commit。非正常退出该session，FLUSH TABLES仍会生效，如使用exit退出锁会被释放。

• 执行SHOW MASTER STATUS语句确定当前的二进制日志文件名和位置

mysql> show master status;
+--------------------+----------+--------------+------------------+-------------------+
| File               | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+--------------------+----------+--------------+------------------+-------------------+
| master_info.000007 |      120 |              |                  |                   |
+--------------------+----------+--------------+------------------+-------------------+
1 row in set (0.01 sec)

• 同步主从数据

如果正在创建一个全新的主从复制可忽略本步骤，如果创建的主库已存在数据，需要创建一个主库的数据快照并在从库中恢复。或许数据快照的方式很多，可使用备份工具如：mysqldump、xtrabackup等，也可直接拷贝主库数据文件。

• 释放读锁

mysql> UNLOCK TABLES;

从库执行CHANGE MASTER TO语句，启动复制

mysql> change master to master_user='repluser',
    -> master_password='mypass',
    -> master_host='192.168.90.129',
    -> master_log_file='master_info.000007',
    -> master_log_pos=120;
Query OK, 0 rows affected, 2 warnings (0.11 sec)

mysql> start slave;            ## 启动复制线程
Query OK, 0 rows affected (0.06 sec)

mysql> show slave status \G;
*************************** 1. row ***************************
               Slave_IO_State: 
                  Master_Host: 192.168.90.129
                  Master_User: repluser
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: master_info.000004
          Read_Master_Log_Pos: 120
               Relay_Log_File: relay-bin.000001
                Relay_Log_Pos: 4
        Relay_Master_Log_File: master_info.000004
             Slave_IO_Running: No
            Slave_SQL_Running: Yes
              Replicate_Do_DB: 
          Replicate_Ignore_DB: mysql,information_schema
           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: 120
              Relay_Log_Space: 120
              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
Master_SSL_Verify_Server_Cert: No
                Last_IO_Errno: 1593
                Last_IO_Error: Fatal error: The slave I/O thread stops because master and slave have
                     equal MySQL server UUIDs; these UUIDs must be different for replication to work.
               Last_SQL_Errno: 0
               Last_SQL_Error: 
  Replicate_Ignore_Server_Ids: 
             Master_Server_Id: 1
                  Master_UUID: 
             Master_Info_File: /home/mysql/slave_a/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: 140716 23:49:33
     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)

提示有相同的UUID,查找原因发现是复制文件时将auto.cnf文件也拷贝过来了，
该文件里面记录了数据库的uuid，每个库的uuid应该是不一样的。

[master]
mysql> show variables like '%server%id%';
+----------------+--------------------------------------+
| Variable_name  | Value                                |
+----------------+--------------------------------------+
| server_id      | 1                                    |
| server_id_bits | 32                                   |
| server_uuid    | 71b00d22-fe27-11e3-bc27-000c29348dbe |
+----------------+--------------------------------------+
3 rows in set (0.03 sec)

[slave]
mysql> show variables like '%server%id%';
+----------------+--------------------------------------+
| Variable_name  | Value                                |
+----------------+--------------------------------------+
| server_id      | 3                                    |
| server_id_bits | 32                                   |
| server_uuid    | 71b00d22-fe27-11e3-bc27-000c29348dbe |
+----------------+--------------------------------------+
3 rows in set (0.03 sec)

解决办法，按照这个16进制格式，随便改下，重启mysql即可

mysql> show variables like '%server%id%';
+----------------+--------------------------------------+
| Variable_name  | Value                                |
+----------------+--------------------------------------+
| server_id      | 3                                    |
| server_id_bits | 32                                   |
| server_uuid    | 71b00d22-fe27-11e3-bc27-000c29348888 |
+----------------+--------------------------------------+
3 rows in set (0.00 sec)

mysql> start slave; 
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> show slave status \G;
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.90.129
                  Master_User: repluser
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: master_info.000004
          Read_Master_Log_Pos: 120
               Relay_Log_File: relay-bin.000003
                Relay_Log_Pos: 285
        Relay_Master_Log_File: master_info.000004
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes
              Replicate_Do_DB: 
          Replicate_Ignore_DB: mysql,information_schema
           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: 120
              Relay_Log_Space: 452
              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: 71b00d22-fe27-11e3-bc27-000c29348dbe
             Master_Info_File: /home/mysql/slave_a/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)

验证同步效果

[master]
mysql> create table test.sysc (
     > id int primary key,
    -> name varchar(10)
    -> );
Query OK, 0 rows affected (0.04 sec)

mysql> insert into test.sysc values(1001,'1001');
Query OK, 1 row affected (0.00 sec)

mysql> insert into test.sysc values(1002,'1002');
Query OK, 1 row affected (0.03 sec)

[slave]
mysql> use test;
Database changed

mysql> show tables;
+----------------+
| Tables_in_test |
+----------------+
| sysc           |
+----------------+
1 row in set (0.00 sec)

mysql> select * from sysc;
+------+------+
| id   | name |
+------+------+
| 1001 | 1001 |
| 1002 | 1002 |
+------+------+
2 rows in set (0.00 sec)

整理自网络

Svoid
2014-07-16