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NSD DBA2 DAY01

  1. 案例1:MySQL一主一从
  2. 案例2:配置主从从同步结构
  3. 配置半同步复制模式

1 案例1:MySQL一主一从

1.1 问题

1.2 方案

使用2台RHEL 7虚拟机,如图-1所示。其中192.168.4.10是MySQL主服务器,负责提供同步源;另一台192.168.4.20作为MySQL从服务器,通过调取主服务器上的binlog日志,在本地重做对应的库、表,实现与主服务器的AB复制(同步)。

图-1

提前为两台MySQL服务器安装好MySQL-server、MySQL-Client软件包,并为数据库用户root修改密码;Linux客户机上则只需安装MySQL-Client软件包即可。

1.3 步骤

实现此案例需要按照如下步骤进行。

步骤一:初始化现有库

为了在启用binlog日志及同步之前保持主、从库的一致性,建议进行初始化——备份主服务器上现有的库,然后导入到从服务器上。

当现有库、表都采用MyISAM引擎时,可执行离线备份、恢复,这样更有效率;否则,可通过mysqldump等工具来实现库的导出、导入。

1)备份MySQL Master(192.168.4.10)上现有的库

如果服务器已经启用binlog,建议对日志做一次重置,否则可忽略:

[root@dbsvr1 ~]# mysql -u root -p
Enter password:  								//以数据库用户root登入
.. ..
mysql> RESET MASTER;  							//重置binlog日志
Query OK, 0 rows affected (0.06 sec)
mysql> quit  									//退出mysql> 环境
Bye

以备份mysql库、sys库为例,导出操作如下:

[root@dbsvr1 ~]# mysqldump -u root -p –all-databases  > /root/mytest.sql
Enter password:  									//验证口令
[root@dbsvr1 ~]# ls -lh /root/mytest.sql  			//确认备份结果
-rw-r--r--. 1 root root 777172 4月  23 12:21 /root/mytest.sql

2)在MySQL Slave(192.168.4.20)上导入备份的库

先清理目标库,避免导入时冲突。主要是采用InnoDB引擎的库,授权库mysql多采用MyISAM引擎,可不做清理。

[root@dbsvr2 ~]# mysql -u root -p
Enter password:  								//以数据库用户root登入
.. ..
mysql> DROP DATABASE test;  						//删除test库
Query OK, 0 rows affected (0.03 sec)
mysql> quit  									//退出mysql> 环境
Bye

使用scp工具下载备份文件:

[root@dbsvr2 ~]# scp /root/mytest.sql  root@192.168.4.20:/
root@dbsvr1's password:  						//验证对方系统用户root的口令
mytest.sql                                  100%  759KB 759.0KB/s   00:00 
[root@dbsvr2 ~]# ls -lh mytest.sql  			//确认下载结果
-rw-r--r--. 1 root root 759K 4月  23 12:22 /mytest.sql

执行导入操作:

[root@dbsvr2 ~]# mysql -u root -p < /mytest.sql
Enter password:  								//验证口令

导入成功后,可重新登入 mysql> 环境,确认清理的目标库已恢复:

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

步骤二:配置MySQL Master(主服务器,192.168.4.10)

1)修改/etc/my.cnf配置,重新启动MySQL服务程序

指定服务器ID号、允许日志同步:

[root@dbsvr1 mysql]# vim /etc/my.cnf
[mysqld]
log_bin=dbsvr1-bin  					//启用binlog日志,并指定文件名前缀
server_id = 10  						//指定服务器ID号
......

重启mysql服务:

[root@dbsvr1 ~]# systemctl  restart mysqld.service

2)新建一个备份用户,授予复制权限

需要的权限为REPLICATION SLAVE,允许其从Slave服务器访问:

mysql> GRANT REPLICATION SLAVE ON *.* TO 'replicater'@'192.168.4.%' IDENTIFIED BY 'pwd123';
Query OK, 0 rows affected, 1 warning (0.09 sec)

3)检查Master服务器的同步状态

在已经初始化现有库的情况下,查看MASTER状态,记录下当前的日志文件名、偏移的位置(下面SLAVE发起复制时需要用到):

mysql> SHOW MASTER STATUS\G
*************************** 1. row ***************************
             File: dbsvr1-bin.000001              //记住当前的日志文件名
         Position: 154                             //记住当前的位置
     Binlog_Do_DB: 
 Binlog_Ignore_DB: 
Executed_Gtid_Set: 
1 row in set (0.00 sec)

步骤三:配置MySQL Slave(从服务器,192.168.4.20)

1)修改/etc/my.cnf配置,重新启动MySQL服务程序

指定服务器ID号、允许日志同步:

[root@dbsvr2 ~]# vim /etc/my.cnf
[mysqld]
log_bin=dbsvr2-bin  					//启动SQL日志,并指定文件名前缀
server_id = 20  						//指定服务器ID号,不要与Master的相同
.. ..

在生产环境中,还可以根据需要设置更详细的同步选项。比如,指定当主、从网络中断时的重试超时时间(slave-net-timeout=60 )等,具体可参考MySQL手册。

配置完成后,重启mysql服务:

[root@dbsvr2 ~]# systemctl  restart mysqld.service 

通过CHANGE MASTER语句指定MASTER服务器的IP地址、同步用户名/密码、起始日志文件、偏移位置(参考MASTER上的状态输出):

mysql> CHANGE MASTER TO MASTER_HOST='192.168.4.10',
    -> MASTER_USER='replicater',
    -> MASTER_PASSWORD='pwd123',
    -> MASTER_LOG_FILE='dbsvr1-bin.000002',  	//对应Master的日志文件
    -> MASTER_LOG_POS=334;  						//对应Master的日志偏移位置
Query OK, 0 rows affected, 2 warnings (0.12 sec)

然后执行START SLAVE(较早版本中为SLAVE START)启动复制:

mysql> START SLAVE;  							//启动复制
Query OK, 0 rows affected (0.00 sec)

注意:一旦启用SLAVE复制,当需要修改MASTER信息时,应先执行STOP SLAVE停止复制,然后重新修改、启动复制。

通过上述连接操作,MASTER服务器的设置信息自动存为master.info文件,以后每次MySQL服务程序时会自动调用并更新,无需重复设置。查看master.info文件的开头部分内容,可验证相关设置:

[root@dbsvr2 ~]# ls -lh /var/lib/mysql/master.info
-rw-r-----. 1 mysql mysql 132 4月  23 12:06 /var/lib/mysql/master.info
[root@dbsvr2 ~]# head /var/lib/mysql/master.info
25
dbsvr1-bin.000001
154
192.168.4.10
replicater
pwd123
3306
60
0

2)检查Slave服务器的同步状态

通过SHOW SLAVE STATUS语句可查看从服务器状态,确认其中的IO线程、SQL线程正常运行,才能成功同步:

mysql> SHOW SLAVE STATUS\G
Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.4.1
                  Master_User: replicater
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: dbsvr1-bin.000001
          Read_Master_Log_Pos: 154
               Relay_Log_File: db2-relay-bin.000003
                Relay_Log_Pos: 321
        Relay_Master_Log_File: dbsvr1-bin.000001
             Slave_IO_Running: Yes             //IO线程应该已运行
            Slave_SQL_Running: Yes             //SQL线程应该已运行
              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: 154
              Relay_Log_Space: 2490
              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: 10
                  Master_UUID: 2d4d8a11-27b7-11e7-ae78-52540055c180
             Master_Info_File: /var/lib/mysql/master.info
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
           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
         Replicate_Rewrite_DB: 
                 Channel_Name: 
           Master_TLS_Version: 
1 row in set (0.00 sec)

若START SLAVE直接报错失败,请检查CHANGE MASTER相关设置是否有误,纠正后再重试;若IO线程或SQL线程有一个为“No”,则应检查服务器的错误日志,分析并排除故障后重启主从复制。

步骤四:测试主从同步效果

1)在Master上操作数据库、表、表记录

新建newdb库、newtable表,随意插入几条表记录:

mysql> CREATE DATABASE newdb;  						//新建库newdb
Query OK, 1 row affected (0.17 sec)

mysql> USE newdb;  									//切换到newdb库
Database changed

mysql> CREATE TABLE newtable(id int(4));  			//新建newtable表
Query OK, 0 rows affected (0.46 sec)

mysql> INSERT INTO newtable VALUES(1234),(5678);  	//插入2条表记录
Query OK, 2 rows affected (0.24 sec)
Records: 2  Duplicates: 0  Warnings: 0
mysql> SELECT * FROM newtable; 						//确认表数据
+------+
| id   |
+------+
| 1234 |
| 5678 |
+------+
2 rows in set (0.00 sec)

2)在Slave上确认自动同步的结果

直接切换到newdb库,并查询newtable表的记录,应该与Master上的一样,这才说明主从同步已经成功生效:

mysql> USE newdb;  									//直接切换到newdb库
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed

mysql> SELECT * FROM newtable;  					//输出表记录
+------+
| id   |
+------+
| 1234 |
| 5678 |
+------+
2 rows in set (0.02 sec)

3)在Master服务器上可查看Slave主机的信息

mysql> SHOW SLAVE HOSTS;
+-----------+------+------+-----------+--------------------------------------+
| Server_id | Host | Port | Master_id | Slave_UUID                           |
+-----------+------+------+-----------+--------------------------------------+
|         2 |      | 3306 |        10 | 512cf7c1-27c4-11e7-8f4b-5254007b030b |
+-----------+------+------+-----------+--------------------------------------+
1 row in set (0.00 sec)

2 案例2:配置主从从同步结构

2.1 问题

2.2 方案

使用3台RHEL 7虚拟机,如图-2所示。其中192.168.4.51是MySQL主服务器,负责提供同步源;另一台192.168.4.52作为192.168.4.51从服务器,最后一台192.168.4.53作为192.168.4.52从服务器,通过调取主服务器上的binlog日志,客户端访问主库51 时 创建库表记录 在52 和53 数据库服务器都可以看到

图-2

2.3 步骤

实现此案例需要按照如下步骤进行。

步骤一:环境准备

为了在启用binlog日志及同步之前保持主、从库的一致性,主从同步未配置之前,要保证从库上要有主库上的数据,禁用selinux,关闭防火墙服务,保证物理连接正常

[root@db51 ~]# systemctl  stop firewalld
[root@db51 ~]# setenforce  0 
[root@db51 ~]# ping   -c   2   192.168.4.51
PING 192.168.4.51 (192.168.4.51) 56(84) bytes of data.
64 bytes from 192.168.4.51: icmp_seq=1 ttl=64 time=0.059 ms
64 bytes from 192.168.4.51: icmp_seq=2 ttl=64 time=0.063 ms

--- 192.168.4.51 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 999ms
rtt min/avg/max/mdev = 0.059/0.061/0.063/0.002 ms
[root@db51 ~]# ping   -c   2   192.168.4.52
PING 192.168.4.52 (192.168.4.52) 56(84) bytes of data.
64 bytes from 192.168.4.52: icmp_seq=1 ttl=64 time=0.698 ms
64 bytes from 192.168.4.52: icmp_seq=2 ttl=64 time=0.365 ms

--- 192.168.4.52 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1000ms
rtt min/avg/max/mdev = 0.365/0.531/0.698/0.168 ms

步骤二:配置主服务器192.168.4.51

1)对yaya用户进行授权

[root@db51 ~]# mysql -uroot -p123456
mysql> grant   replication  slave   on  *.*  to  yaya@"%"   identified    by  "123456";
Query OK, 0 rows affected, 1 warning (0.03 sec)

2)启用binlog日志,修改/etc/my.cnf配置,重新启动MySQL服务程序

指定服务器ID号、允许日志同步:

[root@db51 ~]# vim /etc/my.cnf
[mysqld]
log_bin=db51  					//启用binlog日志,并指定文件名前缀
server_id=51					    //指定服务器ID号
binlog-format="mixed"              // 指定binlog日志格式

重启mysql服务:

[root@db51 ~]# systemctl  restart   mysqld

确保/var/lib/mysql下面有两个文件:

[root@db51 ~]#  ls  /var/lib/mysql/db51.*
/var/lib/mysql/db51.000001  /var/lib/mysql/db51.index

查看主服务正在使用的日志信息

查看主服务器状态,记录下当前的日志文件名、偏移的位置(下面SLAVE发起复制时需要用到):

    mysql> show  master  status;
+-------------+----------+--------------+------------------+-------------------+
| File        | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+-------------+----------+--------------+------------------+-------------------+
| db51.000002 |      437 |              |                  |                   |
+-------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)

步骤三:配置从服务器192.168.4.52

1)在服务器192.168.4.52上对user53用户进行授权

[root@db52 ~]# mysql -u root -p123456
mysql> grant   replication  slave  on  *.*  to   user53@"192.168.4.53"  identified  by "654321";
Query OK, 0 rows affected, 1 warning (0.00 sec)

2)修改/etc/my.cnf配置,启用binlog日志,指定server_id 和 允许级联复制

[root@db52 ~]# vim /etc/my.cnf 
[mysqld]
server_id=52                   
log-bin=db52
binlog-format="mixed"
log_slave_updates                          //允许级联复制

3)配置完成后,重启mysql服务:

[root@db52 ~]# systemctl restart mysqld

4)确保/var/lib/mysql下面有两个文件:

[root@db52 ~]# ls /var/lib/mysql/db52.*
/var/lib/mysql/db52.000001  /var/lib/mysql/db52.index

5)查看正在使用的日志信息

[root@db52 ~]# mysql -uroot -p123456
mysql>  show  master  status;
+-------------+----------+--------------+------------------+-------------------+
| File        | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+-------------+----------+--------------+------------------+-------------------+
| db52.000001 |      154 |              |                  |                   |
+-------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)    //查看日志文件名、偏移的位置

6)验证主库的授权用户

[root@db52 ~]# mysql -h192.168.4.51 -uyaya -p123456

mysql: [Warning] Using a password on the command line interface can be insecure.

Welcome to the MySQL monitor. Commands end with ; or \g.

Your MySQL connection id is 4

Server version: 5.7.17-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>                                //验证成功

7)通过change master语句指定master服务器的IP地址、同步用户名/密码、起始日志文件、偏移位置(参考master上的状态输出):

[root@db52 ~]# mysql -uroot -p123456

mysql> change master to

-> master_host="192.168.4.51",

-> master_user="yaya",

-> master_password="123456",

-> master_log_file="db51.000002",

-> master_log_pos=437;

Query OK, 0 rows affected, 2 warnings (0.43 sec)

8)启动slave进程

mysql> start slave;

Query OK, 0 rows affected (0.03 sec)

9)查看进程状态信息,通过show slave status语句可查看从服务器状态,确认其中的IO线程、SQL线程正常运行,才能成功同步,IO线程和SQL线程必须是Yes

mysql> show slave status \G;

*************************** 1. row ***************************

Slave_IO_State: Waiting for master to send event

Master_Host: 192.168.4.51

Master_User: yaya

Master_Port: 3306

Connect_Retry: 60

Master_Log_File: db51.000002

Read_Master_Log_Pos: 437

Relay_Log_File: db52-relay-bin.000002

Relay_Log_Pos: 315

Relay_Master_Log_File: db51.000002

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: 437

Relay_Log_Space: 521

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: 51

Master_UUID: 81a13101-aa66-11e8-ad11-525400019e62

Master_Info_File: /var/lib/mysql/master.info

SQL_Delay: 0

SQL_Remaining_Delay: NULL

Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates

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

Replicate_Rewrite_DB:

Channel_Name:

Master_TLS_Version:

1 row in set (0.00 sec)

步骤四:配置从服务器192.168.4.53

1)验证主库的授权用户

[root@db53 ~]# mysql  -h192.168.4.52  -uuser53  -p654321
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 7
Server version: 5.7.17-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>                  //验证成功

2)指定server_id

[mysqld]
validate_password_policy=0
validate_password_length=6
server_id=53

3)重新启动服务

[root@db53 ~]# systemctl restart mysqld

4)管理员登录指定主库信息

[root@db53 ~]# mysql -uroot -p123456
mysql> change  master  to 
    -> master_host="192.168.4.52",
    -> master_user="user53",
    -> master_password="654321",
    -> master_log_file=" db52.000001",
    -> master_log_pos=154;
Query OK, 0 rows affected, 2 warnings (0.37 sec)

5)启动slave进程

mysql>  start  slave;
Query OK, 0 rows affected (0.04 sec)

6)查看进程状态信息

mysql> show slave status\G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.4.52
                  Master_User: user53
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: db52.000001
          Read_Master_Log_Pos: 154
               Relay_Log_File: db53-relay-bin.000003
                Relay_Log_Pos: 315
        Relay_Master_Log_File: db52.000001
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes

步骤五:客户端验证配置

1)在主服务器上在主库上授权访问gamedb库的用户

[root@db51 ~]# mysql -uroot  -p123456
mysql> grant  all  on  gamedb.*   to   dada@"%"  identified by  "123456";
Query OK, 0 rows affected, 1 warning (0.03 sec)

2)客户端使用授权用户连接主库,建库、表、插入记录

[root@room9pc01 ~]# mysql  -h192.168.4.51  -udada  -p123456
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MySQL connection id is 7
Server version: 5.7.17-log MySQL Community Server (GPL)

Copyright (c) 2000, 2017, Oracle, MariaDB Corporation Ab and others.

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

MySQL [(none)]>   //验证成功
MySQL [(none)]> create  database  gamedb;   //创建测试库
Query OK, 1 row affected (0.04 sec)
MySQL [(none)]> create  table  gamedb.t1(id int);   //在gamedb下创建t1表
Query OK, 0 rows affected (0.17 sec)
MySQL [(none)]> insert into  gamedb.t1 values(8888);   //在t1表中插入数值
Query OK, 1 row affected (0.22 sec)

3)客户端使用授权用户连接2台从库时,也可以看到主库上新的库表记录

[root@room9pc01 ~]# mysql  -h192.168.4.52  -udada  -p123456  //验证52主机的状态
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MySQL connection id is 10
Server version: 5.7.17-log MySQL Community Server (GPL)

Copyright (c) 2000, 2017, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
MySQL [(none)]> select  * from gamedb.t1;         //查询插入的表格
+------+
| id   |
+------+ 
| 8888 |
+------+
1 row in set (0.00 sec)
MySQL [(none)]> exit
[root@room9pc01 ~]# mysql  -h192.168.4.53  -udada  -p123456 //验证53主机的状态
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MySQL connection id is 6
Server version: 5.7.17 MySQL Community Server (GPL)

Copyright (c) 2000, 2017, Oracle, MariaDB Corporation Ab and others.

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

MySQL [(none)]> select  * from gamedb.t1;
+------+
| id   |
+------+
| 8888 |
+------+
1 row in set (0.00 sec)

3 配置半同步复制模式

3.1 问题

3.2 步骤

实现此案例需要按照如下步骤进行。

步骤一:查看是否允许动态加载模块,

1)查看是否允许动态加载模块默认允许

mysql> show  variables  like  'have_dynamic_loading';
+----------------------+-------+
| Variable_name        | Value |
+----------------------+-------+
| have_dynamic_loading | YES   |
+----------------------+-------+
1 row in set (0.01 sec)

2)命令行加载插件,用户需有SUPER权限

主库上面操作:

mysql> INSTALL PLUGIN rpl_semi_sync_master   SONAME   'semisync_master.so';

从库上面操作:

mysql> INSTALL PLUGIN rpl_semi_sync_slave SONAME  'semisync_slave.so';

查看系统库下的表,模块是否安装成功:

mysql> SELECT  PLUGIN_NAME, PLUGIN_STATUS FROM INFORMATION_SCHEMA.PLUGINS  WHERE PLUGIN_NAME LIKE '%semi%';
+----------------------+---------------+
| PLUGIN_NAME          | PLUGIN_STATUS |
+----------------------+---------------+
| rpl_semi_sync_master | ACTIVE        |
| rpl_semi_sync_slave  | ACTIVE        |
+----------------------+---------------+
2 rows in set (0.00 sec)

3)启用半同步复制,在安装完插件后,半同步复制默认是关闭的

主库上面执行:

mysql> SET GLOBAL rpl_semi_sync_master_enabled = 1;
Query OK, 0 rows affected (0.00 sec)

从库上面执行:

mysql> SET GLOBAL rpl_semi_sync_slave_enabled = 1;
Query OK, 0 rows affected (0.00 sec)

查看半同步复制模式是否启用:

mysql>  show  variables  like  "rpl_semi_sync_%_enabled";
+------------------------------+-------+
| Variable_name                | Value |
+------------------------------+-------+
| rpl_semi_sync_master_enabled | ON    |
| rpl_semi_sync_slave_enabled  | ON    |
+------------------------------+-------+
2 rows in set (0.00 sec)

4)永久启用半同步复制

主库配置

[root@master51 ~]# vim /etc/my.cnf
[mysqld]
plugin-load=rpl_semi_sync_master=semisync_master.so
rpl_semi_sync_master_enabled=1

从库配置

[root@slave52 ~]# vim /etc/my.cnf
[mysqld]
plugin-load=rpl_semi_sync_slave=semisync_slave.so
rpl_semi_sync_slave_enabled=1

在高可用架构下,master和slave需同时启动,以便在切换后能继续使用半同步复制

[root@master51 ~]# vim /etc/my.cnf
[mysqld]
plugin-load \
="rpl_semi_sync_master=semisync_master.so;rpl_semi_sync_slave=semisync_slave.so"
rpl-semi-sync-master-enabled = 1
rpl-semi-sync-slave-enabled = 1