MySQL主从架构

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  MySQL主从又叫做Replication、AB复制。简单讲就是A和B两台机器做主从后，在A上写数据，另外一台B也会跟着写数据，两者数据实时同步的。它基于binlog，主设备上须开启binlog才能进行主从。   主从过程大致有3个步骤：
     1）主设备将更改操作记录到binlog里；
     2）从将主设备的binlog事件(sql语句)同步到从本机上并记录在relaylog里；
     3）从根据relaylog里面的sql语句按顺序执行。
   主设备上有一个log dump线程，用来和从的I/O线程传递binlog。从设备上有两个线程，其中I/O线程用来同步主的binlog并生成relaylog，另外一个SQL线程用来把relaylog里面的sql语句落地。

准备工作
1、准备两台装有mysql的服务器，并启动mysql服务。
2、分配角色，确定设备主从。

配置主设备
1、编辑配置文件

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[iyunv@plinuxos ~]# vim /etc/my.cnf [mysqld] server-id=88 log_bin=bin01

2、重启mysql

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[iyunv@plinuxos ~]# /etc/init.d/mysqld restart Shutting down MySQL.... SUCCESS! Starting MySQL. SUCCESS!

3、检查log_bin

1 2	[iyunv@plinuxos ~]# ls /data/mysql/bin01.* /data/mysql/bin01.000001  /data/mysql/bin01.index

4、创建数据库

1 2	[iyunv@plinuxos mysql]# cd /data/mysql [iyunv@plinuxos mysql]# /usr/local/mysql/bin/mysql -uroot -e 'create database db01'

5、增加测试数据

1 2	[iyunv@plinuxos mysql]# /usr/local/mysql/bin/mysqldump -uroot zrlog >/tmp/zrlog.sql [iyunv@plinuxos mysql]# /usr/local/mysql/bin/mysql -uroot db01 </tmp/zrlog.sql

6、备份所有数据库

1 2	[iyunv@plinuxos mysql]# /usr/local/mysql/bin/mysqldump -uroot db01 > /tmp/db01.sql [iyunv@plinuxos mysql]# /usr/local/mysql/bin/mysqldump -uroot zrlog > /tmp/zrlog.sql

7、创建用户

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[iyunv@plinuxos mysql]# /usr/local/mysql/bin/mysql -uroot Welcome to the MySQL monitor.  Commands end with ; or \g. Your MySQL connection id is 414 Server version: 5.6.35-log MySQL Community Server (GPL) Copyright (c) 2000, 2016, 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 'repl'@'122.112.197.192' identified by '123456'; Query OK, 0 rows affected (0.01 sec)

8、锁表并查看状态

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mysql> flush tables with read lock;  ##锁表，防止写入 Query OK, 0 rows affected (0.01 sec) mysql> show master status;   ##下方两个参数需要在从设备上配置 +--------------+----------+--------------+------------------+-------------------+ | File         | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +--------------+----------+--------------+------------------+-------------------+ | bin01.000001 |    10472 |              |                  |                   | +--------------+----------+--------------+------------------+-------------------+ 1 row in set (0.00 sec)

配置从设备
1、编辑配置文件

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[iyunv@ecs-89c1 mysql]# vi /etc/my.cnf [mysqld] server-id=192

2、重启mysql

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[iyunv@ecs-89c1 mysql]# /etc/init.d/mysqld restart Shutting down MySQL.. SUCCESS! Starting MySQL. SUCCESS!

3、复制主设备数据库备份文件

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[iyunv@ecs-89c1 mysql]# scp 122.112.253.88:/tmp/*.sql /tmp/ The authenticity of host '122.112.253.88 (122.112.253.88)' can't be established. ECDSA key fingerprint is 2e:6e:90:32:87:05:9e:63:63:d6:2d:44:a5:5f:be:51. Are you sure you want to continue connecting (yes/no)? yes Warning: Permanently added '122.112.253.88' (ECDSA) to the list of known hosts. root@122.112.253.88's password: db01.sql                                    100% 9877     9.7KB/s   00:00          zrlog.sql                                   100% 9878     9.7KB/s   00:00

4、创建对应数据库

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[iyunv@ecs-89c1 mysql]# /usr/local/mysql/bin/mysql -uroot Welcome to the MySQL monitor.  Commands end with ; or \g. Your MySQL connection id is 1 Server version: 5.6.35 MySQL Community Server (GPL) Copyright (c) 2000, 2016, 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> create database db01; Query OK, 1 row affected (0.00 sec) mysql> create database zrlog; Query OK, 1 row affected (0.00 sec) [iyunv@ecs-89c1 mysql]# /usr/local/mysql/bin/mysql -uroot db01 </tmp/db01.sql [iyunv@ecs-89c1 mysql]# /usr/local/mysql/bin/mysql -uroot zrlog </tmp/zrlog.sql

5、配置主备同步

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[iyunv@ecs-89c1 mysql]# /usr/local/mysql/bin/mysql -uroot Welcome to the MySQL monitor.  Commands end with ; or \g. Your MySQL connection id is 4 Server version: 5.6.35 MySQL Community Server (GPL) Copyright (c) 2000, 2016, 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> stop slave; Query OK, 0 rows affected, 1 warning (0.00 sec) mysql> change master to master_host='122.112.253.88',master_user='repl',master_password='123456',master_log_file='bin01.000001',master_log_pos=10472; Query OK, 0 rows affected, 2 warnings (0.03 sec) mysql> start slave; Query OK, 0 rows affected (0.01 sec)

6、查看主从状态

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mysql> show slave status\G;  ##如果出现错误，可能是云主机策略没放过3306端口 *************************** 1. row ***************************                Slave_IO_State: Waiting for master to send event                   Master_Host: 122.112.253.88                   Master_User: repl                   Master_Port: 3306                 Connect_Retry: 60               Master_Log_File: bin01.000001           Read_Master_Log_Pos: 10708                Relay_Log_File: ecs-89c1-relay-bin.000003                 Relay_Log_Pos: 515         Relay_Master_Log_File: bin01.000001              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: 10708               Relay_Log_Space: 691               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: 88                   Master_UUID: 79b66469-8cc8-11e7-ae36-fa163eb51d35              Master_Info_File: /data/mysql/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) ERROR: No query specified

7、主设备解锁

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[iyunv@plinuxos mysql]# /usr/local/mysql/bin/mysql -uroot Welcome to the MySQL monitor.  Commands end with ; or \g. Your MySQL connection id is 875 Server version: 5.6.35-log MySQL Community Server (GPL) Copyright (c) 2000, 2016, 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> unlock tables; Query OK, 0 rows affected (0.00 sec)

测试主从同步
1、在主设备上删除db01数据库的表；

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mysql> show tables; +----------------+ | Tables_in_db01 | +----------------+ | comment        | | link           | | log            | | lognav         | | plugin         | | tag            | | type           | | user           | +----------------+ 8 rows in set (0.00 sec) mysql> drop table tag; Query OK, 0 rows affected (0.01 sec)

2、在从设备查看对应的表也已经不存在了。

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mysql> show tables; +----------------+ | Tables_in_db01 | +----------------+ | comment        | | link           | | log            | | lognav         | | plugin         | | type           | | user           | +----------------+ 7 rows in set (0.00 sec)

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扩展学习
▎配置参数

1. 主服务器上：
binlog-do-db=      //仅同步指定的库(其他库不同步)
binlog-ignore-db= //忽略指定库(其他库都同步)
2. 从服务器上：
replicate_do_db=   //(不常用)
replicate_ignore_db=   //(不常用)
replicate_do_table=   //(不常用)
replicate_ignore_table=   //(不常用)
replicate_wild_do_table=   //如aming.%, (支持通配符%)
replicate_wild_ignore_table=