半同步复制的实现

1、在主服务器上的配置

1）安装mariadb-server

[root@localhost ~]# yum -y install mariadb-server

2）编辑/etc/my.cnf

[root@localhost ~]# vim /etc/my.cnf    skip_name_resolve = ON    innodb_file_per_table = ON    server-id = 1    log-bin = master-log

3）授权可以复制本地数据库信息的主机

[root@localhost ~]# systemctl start mariadb.service （启动mariadb server）[root@localhost ~]# mysql    MariaDB [(none)]> grant replication slave,replication client on *.* to 'repluser'@'10.1.51.%' identified by 'replpasswd';    MariaDB [(none)]> flush privileges;MariaDB [(none)]> show master status\G （查看主服务器的状态信息，在从服务器中要用到）*************************** 1. row ***************************            File: master-log.000003 （正在使用的二进制日志文件）        Position: 245 （所处的位置）    Binlog_Do_DB: Binlog_Ignore_DB:

4）安装rplsemisync_master插件，并启用

[root@localhost ~]# mysqlMariaDB [(none)]> install plugin rpl_semi_sync_master soname 'semisync_master.so';MariaDB [(none)]> set global rpl_semi_sync_master_enabled = ON; 补充：MariaDB [(none)]> show plugins;（可查看插件是否激活）MariaDB [(none)]> show global variables like 'rpl_semi%';（可查看安装的插件是否启用）MariaDB [(none)]> show global status like '%semi%';（可查看从服务器的个数，此时是0个）

2、从服务器的配置

1）安装mariadb-server

[root@localhost ~]# yum -y install mariadb-server

2）编辑/etc/my.cnf文件

[root@localhost ~]# vim /etc/my.cnf    在[mysqld]段的最后添加以下内容    skip_name_resolve = ON    innodb_file_per_table = ON    server-id = 2 （id号不能跟主服务器相同）    relay-log = slave-log （自定义二进制日志文件名）

3）设置要从哪个主服务器的那个位置开始同步

[root@localhost ~]# systemctl start mariadb.service[root@localhost ~]# mysql    MariaDB [(none)]> change master to master_host='10.1.51.60',master_user='repluser',master_password='replpasswd',master_log_file='master-log.000003',master_log_pos=245;

4）安装rplsemisync_slave插件并启用

[root@localhost ~]# mysql       MariaDB [(none)]> install plugin rpl_semi_sync_slave soname 'semisync_slave.so';    MariaDB [(none)]> set global rpl_semi_sync_slave_enabled = ON;    MariaDB [(none)]> start slave;

完成上面配置后，可以在主服务器上查看半同步复制的相关信息，命令如下：

MariaDB [(none)]> show global status like '%semi%';    Rpl_semi_sync_master_clients    1 （从服务器有一台）

3、测试

测试以个人实际情况而定

1）在主服务器上导入事先准备好的数据库hellodb.sql

MariaDB [hellodb]> source /root/hellodb.sql;

2）在主服务器上查看半同步复制的状态

MariaDB [hellodb]> show master status;+-------------------+----------+--------------+------------------+| File              | Position | Binlog_Do_DB | Binlog_Ignore_DB |+-------------------+----------+--------------+------------------+| master-log.000003 |     8102 |              |                  |+-------------------+----------+--------------+------------------+MariaDB [hellodb]> show global status like '%semi%';+--------------------------------------------+-------+| Variable_name                              | Value |+--------------------------------------------+-------+| Rpl_semi_sync_master_clients               | 1     || Rpl_semi_sync_master_net_avg_wait_time     | 1684  || Rpl_semi_sync_master_net_wait_time         | 60630 || Rpl_semi_sync_master_net_waits             | 36    || Rpl_semi_sync_master_no_times              | 1     || Rpl_semi_sync_master_no_tx                 | 1     || Rpl_semi_sync_master_status                | ON    || Rpl_semi_sync_master_timefunc_failures     | 0     || Rpl_semi_sync_master_tx_avg_wait_time      | 1884  || Rpl_semi_sync_master_tx_wait_time          | 65965 || Rpl_semi_sync_master_tx_waits              | 35    || Rpl_semi_sync_master_wait_pos_backtraverse | 0     || Rpl_semi_sync_master_wait_sessions         | 0     || Rpl_semi_sync_master_yes_tx                | 35    |+--------------------------------------------+-------+

3）在从服务器上查看是否同步

MariaDB [(none)]> show databases;MariaDB [(none)]> use hellodb;MariaDB [hellodb]> select * from students;

补充：基于上面的半同步复制配置复制的过滤器，复制过滤最好在从服务器上设置，步骤如下

1、从服务器的配置

1）关闭mariadb server

[root@localhost ~]# systemctl stop mariadb.service

2）编辑/etc/my.cnf文件

[root@localhost ~]# vim /etc/my.cnf    skip_name_resolve = ON    innodb_file_per_table = ON    server-id = 2    relay-log = slave-log    replicate-do-db = mydb （只复制mydb数据库的内容）补充：常用的过滤选项如下    Replicate_Do_DB=    Replicate_Ignore_DB=    Replicate_Do_Table=    Replicate_Ignore_Table=    Replicate_Wild_Do_Table=    Replicate_Wild_Ignore_Table=

3）重启mariadb server

[root@localhost ~]# systemctl start mariadb.service

4）重启mariadb server后，半同步复制功能将被关闭，因此要重新启动

MariaDB [(none)]> show global variables like '%semi%';+---------------------------------+-------+| Variable_name                   | Value |+---------------------------------+-------+| rpl_semi_sync_slave_enabled     | OFF   || rpl_semi_sync_slave_trace_level | 32    |+---------------------------------+-------+MariaDB [(none)]> set global rpl_semi_sync_slave_enabled = ON;MariaDB [(none)]> stop slave;（需先关闭从服务器复制功能再重启）MariaDB [(none)]> start slave;

2、测试

1）主服务器上的hellodb数据库创建一个新表semitable

MariaDB [hellodb]> create table semitable (id int);

2）在从服务器上查看hellodb数据库是否有semitable

MariaDB [(none)]> use hellodbMariaDB [hellodb]> show tables;（并没有）+-------------------+| Tables_in_hellodb |+-------------------+| classes           || coc               || courses           || scores            || students          || teachers          || toc               |+-------------------+

3）在主服务器上创建mydb数据库，并为其创建一个tbl1表

MariaDB [hellodb]> create database mydb;

4）在从服务器上查看mydb数据库的是否有tbl1表

MariaDB [hellodb]> use mydb;MariaDB [mydb]> show tables; （可以查看到）+----------------+| Tables_in_mydb |+----------------+| tbl1           |+----------------+