Mysql双主双从（实战干货，好文章！！）

1.机器说明

 

 

因为主2，从2，都是通过同一个镜像生成的系统，所以MySQL的 server-uuid 是一样的，在配置前，需要做以下操作

重命名 /var/lib/mysql/auto.cnf 文件

mv auto.cnf auto.cnf.bak

重启mysql 重新生成 auto.cnf 文件

 

 

 

 

因为之前配置过 ali-shuidi01,ali-shuidi02的主从关系，所以先将两者之前的主从关系取消，在master1上执行

1. mysql> stop slave;
2. Query OK, 0 rows affected, 1 warning (0.00 sec)
3.  
4. mysql> reset master;
5. Query OK, 0 rows affected (0.01 sec)

 

2. master1 配置文件修改

vim /etc/my.cnf

 

1. #主服务器唯一ID
2. server-id=1
3. #启用二进制日志
4. log-bin=mysql-bin
5. # 设置不要复制的数据库(可设置多个)
6. binlog-ignore-db=mysql
7. binlog-ignore-db=information_schema
8. binlog-ignore-db=performance_schema
9. binlog-ignore-db=sys
10. #设置需要复制的数据库
11. binlog-do-db=copydb2
12. #设置logbin格式
13. binlog_format=STATEMENT
14. # 在作为从数据库的时候，有写入操作也要更新二进制日志文件
15. log-slave-updates
16. #表示自增长字段每次递增的量，指自增字段的起始值，其默认值是1，取值范围是1 .. 65535
17. auto-increment-increment=2
18. # 表示自增长字段从哪个数开始，指字段一次递增多少，他的取值范围是1 .. 65535
19. auto-increment-offset=1

 

3. master2 配置文件修改

vim /etc/my.cnf

 

1. #主服务器唯一ID
2. server-id=3
3. #启用二进制日志
4. log-bin=mysql-bin
5. # 设置不要复制的数据库(可设置多个)
6. binlog-ignore-db=mysql
7. binlog-ignore-db=information_schema
8. binlog-ignore-db=performance_schema
9. binlog-ignore-db=sys
10. #设置需要复制的数据库
11. binlog-do-db=copydb2
12. #设置logbin格式
13. binlog_format=STATEMENT
14. # 在作为从数据库的时候，有写入操作也要更新二进制日志文件
15. log-slave-updates
16. #表示自增长字段每次递增的量，指自增字段的起始值，其默认值是1，取值范围是1 .. 65535
17. auto-increment-increment=2
18. # 表示自增长字段从哪个数开始，指字段一次递增多少，他的取值范围是1 .. 65535
19. auto-increment-offset=2

 

4. slave1 配置文件修改

vim /etc/my.cnf

 

1. #从服务器唯一ID
2. server-id=2
3. #启用中继日志
4. relay-log=mysql-relay

 

5. slave2配置文件修改

 

vim /etc/my.cnf

 

1. #从服务器唯一ID
2. server-id=4 #启用中继日志
3. relay-log=mysql-relay

 

6. 双主机、双从机重启 mysql 服务, 主机从机都关闭防火墙

 

1. [root@shuidi01 etc]# systemctl restart mysqld
2. [root@shuidi01 etc]# systemctl status mysqld
3. ● mysqld.service - MySQL Server
4. Loaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled)
5. Active: active (running) since 一 2020-03-30 20:38:23 CST; 6s ago
6. Docs: man:mysqld(8)
7. http://dev.mysql.com/doc/refman/en/using-systemd.html
8. Process: 9985 ExecStart=/usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid $MYSQLD_OPTS (code=exited, status=0/SUCCESS)
9. Process: 9946 ExecStartPre=/usr/bin/mysqld_pre_systemd (code=exited, status=0/SUCCESS)
10. Main PID: 9990 (mysqld)
11. CGroup: /system.slice/mysqld.service
12. └─9990 /usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid
13.  
14. 3月 30 20:38:22 shuidi01 systemd[1]: Starting MySQL Server...
15. 3月 30 20:38:23 shuidi01 systemd[1]: Started MySQL Server.

 

1. [root@shuidi02 etc]# systemctl restart mysqld
2. [root@shuidi02 etc]# systemctl status mysqld
3. ● mysqld.service - MySQL Server
4. Loaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled)
5. Active: active (running) since 一 2020-03-30 20:39:10 CST; 7s ago
6. Docs: man:mysqld(8)
7. http://dev.mysql.com/doc/refman/en/using-systemd.html
8. Process: 868 ExecStart=/usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid $MYSQLD_OPTS (code=exited, status=0/SUCCESS)
9. Process: 845 ExecStartPre=/usr/bin/mysqld_pre_systemd (code=exited, status=0/SUCCESS)
10. Main PID: 873 (mysqld)
11. CGroup: /system.slice/mysqld.service
12. └─873 /usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid
13.  
14. 3月 30 20:39:09 shuidi02 systemd[1]: Starting MySQL Server...
15. 3月 30 20:39:10 shuidi02 systemd[1]: Started MySQL Server.

 

1. [root@shuidi03 etc]# systemctl restart mysqld
2. [root@shuidi03 etc]# systemctl status mysqld
3. ● mysqld.service - MySQL Server
4. Loaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled)
5. Active: active (running) since 一 2020-03-30 20:39:42 CST; 5s ago
6. Docs: man:mysqld(8)
7. http://dev.mysql.com/doc/refman/en/using-systemd.html
8. Process: 8507 ExecStart=/usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid $MYSQLD_OPTS (code=exited, status=0/SUCCESS)
9. Process: 8485 ExecStartPre=/usr/bin/mysqld_pre_systemd (code=exited, status=0/SUCCESS)
10. Main PID: 8512 (mysqld)
11. CGroup: /system.slice/mysqld.service
12. └─8512 /usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid
13.  
14. 3月 30 20:39:41 shuidi03 systemd[1]: Starting MySQL Server...
15. 3月 30 20:39:42 shuidi03 systemd[1]: Started MySQL Server.

 

1. [root@shuidi04 etc]# systemctl restart mysqld
2. [root@shuidi04 etc]# systemctl status mysqld
3. ● mysqld.service - MySQL Server
4. Loaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled)
5. Active: active (running) since 一 2020-03-30 20:40:13 CST; 8s ago
6. Docs: man:mysqld(8)
7. http://dev.mysql.com/doc/refman/en/using-systemd.html
8. Process: 8861 ExecStart=/usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid $MYSQLD_OPTS (code=exited, status=0/SUCCESS)
9. Process: 8839 ExecStartPre=/usr/bin/mysqld_pre_systemd (code=exited, status=0/SUCCESS)
10. Main PID: 8866 (mysqld)
11. CGroup: /system.slice/mysqld.service
12. └─8866 /usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid
13.  
14. 3月 30 20:40:12 shuidi04 systemd[1]: Starting MySQL Server...
15. 3月 30 20:40:13 shuidi04 systemd[1]: Started MySQL Server.

 

7. 在两台主机上建立账户并授权 slave

master1:

1. mysql> GRANT REPLICATION SLAVE ON *.* TO 'slave'@'%' IDENTIFIED BY 'Zan_666888';
2. Query OK, 0 rows affected, 1 warning (0.00 sec)
3. #查询Master1的状态
4. mysql> show master status;
5. +------------------+----------+--------------+-------------------------------------------------+-------------------+
6. | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
7. +------------------+----------+--------------+-------------------------------------------------+-------------------+
8. | mysql-bin.000002 | 435 | copydb2 | mysql,information_schema,performance_schema,sys | |
9. +------------------+----------+--------------+-------------------------------------------------+-------------------+
10. 1 row in set (0.00 sec)

master2:

1. mysql> GRANT REPLICATION SLAVE ON *.* TO 'slave'@'%' IDENTIFIED BY 'Zan_666888';
2. Query OK, 0 rows affected, 1 warning (0.01 sec)
3. #查询Master2的状态
4. mysql> show master status;
5. +------------------+----------+--------------+-------------------------------------------------+-------------------+
6. | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
7. +------------------+----------+--------------+-------------------------------------------------+-------------------+
8. | mysql-bin.000001 | 435 | copydb2 | mysql,information_schema,performance_schema,sys | |
9. +------------------+----------+--------------+-------------------------------------------------+-------------------+
10. 1 row in set (0.00 sec)

#分别记录下File和Position的值

#执行完此步骤后不要再操作主服务器MYSQL，防止主服务器状态值变化

 

8. 在从机上配置需要复制的主机

Slava1 复制 Master1，Slava2 复制 Master2

 

1. #复制主机的命令
2. CHANGE MASTER TO MASTER_HOST='主机的IP地址',
3. MASTER_USER='slave',
4. MASTER_PASSword='123123',
5. MASTER_LOG_FILE='mysql-bin.具体数字',MASTER_LOG_POS=具体值;

slave1:

1. CHANGE MASTER TO MASTER_HOST='172.16.94.131',
2. MASTER_USER='slave',
3. MASTER_PASSWORD='Zan_666888',
4. MASTER_LOG_FILE='mysql-bin.000002',MASTER_LOG_POS=435;

slave2:

1. CHANGE MASTER TO MASTER_HOST='172.16.94.133',
2. MASTER_USER='slave',
3. MASTER_PASSWORD='Zan_666888',
4. MASTER_LOG_FILE='mysql-bin.000001',MASTER_LOG_POS=435;

#启动两台从服务器复制功能

slave1:

1. mysql> start slave;
2. #查看从服务器状态
3. show slave statusG;

 

slave2:

mysql> start slave; #查看从服务器状态 show slave statusG;

 

#下面两个参数都是Yes，则说明主从配置成功！

# Slave_IO_Running: Yes

# Slave_SQL_Running: Yes

 

9. 两个主机互相复制

Master2 复制 Master1，Master1 复制 Master2

 

master2:

1. mysql> CHANGE MASTER TO MASTER_HOST='172.16.94.131',
2. -> MASTER_USER='slave',
3. -> MASTER_PASSWORD='Zan_666888',
4. -> MASTER_LOG_FILE='mysql-bin.000002',MASTER_LOG_POS=435;
5. Query OK, 0 rows affected, 2 warnings (0.02 sec)
6.  
7. mysql> start slave;
8. Query OK, 0 rows affected (0.00 sec)
9.  
10. mysql> show slave statusG;

 

 

master1:

 

1. mysql> CHANGE MASTER TO MASTER_HOST='172.16.94.133',
2. -> MASTER_USER='slave',
3. -> MASTER_PASSWORD='Zan_666888',
4. -> MASTER_LOG_FILE='mysql-bin.000001',MASTER_LOG_POS=435;
5. Query OK, 0 rows affected, 2 warnings (0.02 sec)
6.  
7. mysql> start slave;
8. Query OK, 0 rows affected (0.00 sec)
9.  
10. mysql> show slave statusG;

 

 

#下面两个参数都是Yes，则说明主从配置成功！

# Slave_IO_Running: Yes

# Slave_SQL_Running: Yes

 

10. Master1 主机新建库、新建表、insert 记录，Master2 和从机复制

1. mysql> CREATE DATABASE copydb2;
2. Query OK, 1 row affected (0.00 sec)
3.  
4. mysql> show databases;
5. +--------------------+
6. | Database |
7. +--------------------+
8. | information_schema |
9. | copydb |
10. | copydb2 |
11. | mysql |
12. | nacos_config |
13. | performance_schema |
14. | seata |
15. | seata_account |
16. | seata_order |
17. | seata_storage |
18. | sys |
19. +--------------------+
20. 11 rows in set (0.00 sec)
21.  
22. mysql> use copydb2;
23. Database changed
24. mysql> CREATE TABLE mytbl(id INT,NAME VARCHAR(20));
25. Query OK, 0 rows affected (0.01 sec)
26.  
27. mysql> INSERT INTO mytbl VALUES(1,'zhang3');
28. Query OK, 1 row affected (0.01 sec)
29.  
30. mysql> select * from mytbl;
31. +------+--------+
32. | id | NAME |
33. +------+--------+
34. | 1 | zhang3 |
35. +------+--------+
36. 1 row in set (0.00 sec)

 

 

四个节点数据均实现了同步

 

11.如何停止从服务复制功能

stop slave;

如何重新配置主从

stop slave; reset master;

 

12.修改 Mycat 的配置文件
/usr/local/mycat/conf/schema.xml

修改<dataHost>的balance属性，通过此属性配置读写分离的类型

 

负载均衡类型，目前的取值有4 种：

（1）balance="0", 不开启读写分离机制，所有读操作都发送到当前可用的 writeHost 上。

（2）balance="1"，全部的 readHost 与 stand by writeHost 参与 select 语句的负载均衡，简单地说，当双主双从

模式(M1->S1，M2->S2，并且 M1 与 M2 互为主备)，正常情况下，M2,S1,S2 都参与 select 语句的负载均衡。

（3）balance="2"，所有读操作都随机的在 writeHost、readhost 上分发。

（4）balance="3"，所有读请求随机的分发到 readhost 执行，writerHost 不负担读压力

 

为了双主双从读写分离balance设置为1

 

1. <?xml version="1.0"?>
2. <!DOCTYPE mycat:schema SYSTEM "schema.dtd">
3. <mycat:schema xmlns:mycat="http://io.mycat/">
4.  
5. <schema name="TESTDB" checkSQLschema="false" sqlMaxLimit="100" dataNode="dn1">
6.  
7. </schema>
8.  
9. <dataNode name="dn1" dataHost="host1" database="copydb2" />
10.  
11. <dataHost name="host1" maxCon="1000" minCon="10" balance="1"
12. writeType="0" dbType="mysql" dbDriver="native" switchType="1" slaveThreshold="100">
13. <heartbeat>select user()</heartbeat>
14.  
15. <writeHost host="hostM1" url="172.16.94.131:3306" user="root"
16. password="Zan_123456">
17.  
18. <readHost host="hostS1" url="172.16.94.132:3306" user="root" password="Zan_123456" />
19. </writeHost>
20.  
21. <writeHost host="hostM2" url="172.16.94.133:3306" user="root"
22. password="Zan_123456">
23.  
24. <readHost host="hostS2" url="172.16.94.134:3306" user="root" password="Zan_123456" />
25. </writeHost>
26.  
27. </dataHost>
28.  
29. </mycat:schema>

#balance="1": 全部的readHost与stand by writeHost参与select语句的负载均衡。

#writeType="0": 所有写操作发送到配置的第一个writeHost，第一个挂了切到还生存的第二个

#writeType="1"，所有写操作都随机的发送到配置的 writeHost，1.5 以后废弃不推荐

#writeHost，重新启动后以切换后的为准，切换记录在配置文件中:dnindex.properties 。

#switchType="1": 1 默认值，自动切换。

# -1 表示不自动切换

# 2 基于 MySQL 主从同步的状态决定是否切换。

 

13.启动 Mycat,验证读写分离

1. [root@shuidi01 bin]# ./mycat stop
2. Stopping Mycat-server...
3. Mycat-server was not running.
4. [root@shuidi01 bin]# ./mycat start
5. Starting Mycat-server...

 

 

1. #登录mycat
2. mysql -umycat -pzan123456 -P 8066 -h 127.0.0.1
3. #插入数据
4. mysql> show databases;
5. +----------+
6. | DATABASE |
7. +----------+
8. | TESTDB |
9. +----------+
10. 1 row in set (0.00 sec)
11.  
12. mysql> use TESTDB;
13. Reading table information for completion of table and column names
14. You can turn off this feature to get a quicker startup with -A
15.  
16. Database changed
17. mysql> show tables;
18. +-------------------+
19. | Tables_in_copydb2 |
20. +-------------------+
21. | mytbl |
22. +-------------------+
23. 1 row in set (0.00 sec)
24. mysql> INSERT INTO mytbl VALUES(2,@@hostname);
25. Query OK, 1 row affected, 1 warning (0.00 sec)
26.  
27. mysql> select * from mytbl;
28. +------+----------+
29. | id | NAME |
30. +------+----------+
31. | 1 | zhang3 |
32. | 2 | shuidi03 |
33. +------+----------+
34. 2 rows in set (0.00 sec)
35.  
36. mysql> select * from mytbl;
37. +------+----------+
38. | id | NAME |
39. +------+----------+
40. | 1 | zhang3 |
41. | 2 | shuidi02 |
42. +------+----------+
43. 2 rows in set (0.00 sec)
44. mysql> select * from mytbl;
45. +------+----------+
46. | id | NAME |
47. +------+----------+
48. | 1 | zhang3 |
49. | 2 | shuidi04 |
50. +------+----------+
51. 2 rows in set (0.00 sec)

 

#在Mycat里查询mytbl表,可以看到查询语句在Master2（shuidi03）、Slava1（shuidi02）、Slava2（shuidi04）主从三个主机间切换

 

14.抗风险能力

#停止数据库Master1

1. [root@shuidi01 logs]# systemctl stop mysqld
2. [root@shuidi01 logs]# systemctl status mysqld
3. ● mysqld.service - MySQL Server
4. Loaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled)
5. Active: inactive (dead) since 一 2020-03-30 21:31:28 CST; 4s ago
6. Docs: man:mysqld(8)
7. http://dev.mysql.com/doc/refman/en/using-systemd.html
8. Process: 9985 ExecStart=/usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid $MYSQLD_OPTS (code=exited, status=0/SUCCESS)
9. Process: 9946 ExecStartPre=/usr/bin/mysqld_pre_systemd (code=exited, status=0/SUCCESS)
10. Main PID: 9990 (code=exited, status=0/SUCCESS)
11.  
12. 3月 30 20:38:22 shuidi01 systemd[1]: Starting MySQL Server...
13. 3月 30 20:38:23 shuidi01 systemd[1]: Started MySQL Server.
14. 3月 30 21:31:16 shuidi01 systemd[1]: Stopping MySQL Server...
15. 3月 30 21:31:28 shuidi01 systemd[1]: Stopped MySQL Server.

 

#在Mycat里插入数据依然成功，Master2自动切换为写主机

1. mysql> INSERT INTO mytbl VALUES(3,@@hostname);
2. Query OK, 1 row affected, 1 warning (0.00 sec)
3. mysql> select * from mytbl;
4. +------+----------+
5. | id | NAME |
6. +------+----------+
7. | 1 | zhang3 |
8. | 2 | shuidi04 |
9. | 3 | shuidi04 |
10. +------+----------+
11. 3 rows in set (0.00 sec)

 

#启动数据库Master1

1. [root@shuidi01 logs]# systemctl start mysqld
2. [root@shuidi01 logs]# systemctl status mysqld
3. ● mysqld.service - MySQL Server
4. Loaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled)
5. Active: active (running) since 一 2020-03-30 21:33:39 CST; 2s ago
6. Docs: man:mysqld(8)
7. http://dev.mysql.com/doc/refman/en/using-systemd.html
8. Process: 3527 ExecStart=/usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid $MYSQLD_OPTS (code=exited, status=0/SUCCESS)
9. Process: 3473 ExecStartPre=/usr/bin/mysqld_pre_systemd (code=exited, status=0/SUCCESS)
10. Main PID: 3531 (mysqld)
11. CGroup: /system.slice/mysqld.service
12. └─3531 /usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid
13.  
14. 3月 30 21:33:38 shuidi01 systemd[1]: Starting MySQL Server...
15. 3月 30 21:33:39 shuidi01 systemd[1]: Started MySQL Server.

 

1. mysql> select * from mytbl;
2. +------+----------+
3. | id | NAME |
4. +------+----------+
5. | 1 | zhang3 |
6. | 2 | shuidi01 |
7. | 3 | shuidi01 |
8. +------+----------+
9. 3 rows in set (0.00 sec)
10. mysql> select * from mytbl;
11. +------+----------+
12. | id | NAME |
13. +------+----------+
14. | 1 | zhang3 |
15. | 2 | shuidi02 |
16. | 3 | shuidi02 |
17. +------+----------+
18. 3 rows in set (0.00 sec)
19. mysql> select * from mytbl;
20. +------+----------+
21. | id | NAME |
22. +------+----------+
23. | 1 | zhang3 |
24. | 2 | shuidi04 |
25. | 3 | shuidi04 |
26. +------+----------+
27. 3 rows in set (0.00 sec)

 

#在Mycat里查询mytbl表,可以看到查询语句在Master1（shuidi01）、Slava1（shuidi02）、Slava2（shuidi04）

主从三个主机间切换

Master1、Master2 互做备机，负责写的主机宕机，备机切换负责写操作，保证数据库读写分离高

可用性。