下面实验是基于http://5073392.blog.51cto.com/5063392/1536487搭建的

1） 在master上安装插件
mysql> install plugin rpl_semi_sync_master SONAME 'semisync_master.so';
Query OK, 0 rows affected (0.18 sec)

2）在salve上安装插件
mysql> INSTALL PLUGIN rpl_semi_sync_slave SONAME 'semisync_slave.so';

3）激活半同步复制
master：
mysql> SET GLOBAL rpl_semi_sync_master_enabled = on;

slave：
mysql> SET GLOBAL rpl_semi_sync_slave_enabled = on;

mysql> STOP SLAVE IO_THREAD; START SLAVE IO_THREAD;

4） 确认半同步正在工作
master：
mysql> SHOW STATUS LIKE 'Rpl_semi_sync_master_status';
+-----------------------------+-------+
| Variable_name               | Value |
+-----------------------------+-------+
| Rpl_semi_sync_master_status | ON    |
+-----------------------------+-------+
1 row in set (0.00 sec)

salve：
mysql> SHOW STATUS LIKE 'Rpl_semi_sync_slave_status';
+----------------------------+-------+
| Variable_name              | Value |
+----------------------------+-------+
| Rpl_semi_sync_slave_status | ON    |
+----------------------------+-------+
1 row in set (0.04 sec)

5） 在master上确认半同步模式下至少连了一台从机
mysql> SHOW STATUS LIKE 'Rpl_semi_sync_master_clients';
+------------------------------+-------+
| Variable_name                | Value |
+------------------------------+-------+
| Rpl_semi_sync_master_clients | 1     |
+------------------------------+-------+
1 row in set (0.00 sec)

6）在master上确认复制是否在半同步模式下运行
mysql> SHOW STATUS LIKE 'Rpl_semi_sync_master_yes_tx';
+-----------------------------+-------+
| Variable_name               | Value |
+-----------------------------+-------+
| Rpl_semi_sync_master_yes_tx | 0     |
+-----------------------------+-------+
1 row in set (0.00 sec)

mysql> use test;
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> insert into test values (3);
Query OK, 1 row affected (0.01 sec)

mysql> SHOW STATUS LIKE 'Rpl_semi_sync_master_yes_tx';
+-----------------------------+-------+
| Variable_name               | Value |
+-----------------------------+-------+
| Rpl_semi_sync_master_yes_tx | 1     |
+-----------------------------+-------+
1 row in set (0.00 sec)

mysql> insert into test values (4);
Query OK, 1 row affected (0.01 sec)

mysql> SHOW STATUS LIKE 'Rpl_semi_sync_master_yes_tx';
+-----------------------------+-------+
| Variable_name               | Value |
+-----------------------------+-------+
| Rpl_semi_sync_master_yes_tx | 2     |
+-----------------------------+-------+
1 row in set (0.00 sec)