MariaDB半同步测试

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技术图片

环境:

  • 192.168.205.17: as master server
  • 192.168.205.27: as slave server
  • 192.168.205.37: as slave server

版本:

  • OS: centos 7 1810 with mini install
  • mariadb-5.5.60

目地:

默认情况下,mysql的复制功能是异步的,异步复制可以提供最佳的性能,主库把binlog日志发送给从库即结束,并不验证从库是否接收完毕。这意味着当主服务器或从服务器端发生故障时,有可能从服务器没有接收到主服务器发送过来的binlog日志,这就会造成主服务器和从服务器的数据不一致,甚至在恢复时造成数据的丢失, 半同步解决了性能和数据安全综合,在同步从服务器时只要有一个从服务器确认同步完成,即返回结果,不用等到全部复制完成,这样解决了数据同步复制时要等所有从服务器返回结果,实现了最佳性能和数据安全的结合

步骤:

  1. 安装数据库在所有服务器,初始化运行以下脚本
        [root@master ~]#cat /data/maridb_yum.sh 
    rpm -q mariadb-server ||yum install -y mariadb-server
    mkdir /data/mysql,logs
    chown mysql:mysql /data/mysql,logs
    sed -i ‘/\[mysqld\]/a log-bin=/data/logs/bin‘ /etc/my.cnf
    sed -i ‘/\[mysqld\]/a innodb_file_per_table = on‘ /etc/my.cnf
    sed -i ‘/\[mysqld\]/a skip_name_resolve = on‘ /etc/my.cnf
    sed -i ‘s@(datadir=).*@\1/data/mysql@‘ /etc/my.cnf 
  2. 修改配置文件
    [root@master ~]#vi /etc/my.cnf
    [mysqld]
    server-id=17
    [root@slave1 ~]#vi /etc/my.cnf
    [mysqld]
    server-id=27    
    [root@slave2 ~]#vi /etc/my.cnf
    [mysqld]
    server-id=37  
  3. 主服务器上建立同步帐号及,记录位置或备份主服器恢复从服务器二选一
    MariaDB [(none)]> grant replication slave on *.* to repluser@‘192.168.205.%‘ identified by ‘centos‘;
    MariaDB [(none)]> show master logs;                                                                 
    +------------+-----------+
    | Log_name   | File_size |
    +------------+-----------+
    | bin.000001 |     30373 |
    | bin.000002 |   1038814 |
    | bin.000003 |       406 |
    +------------+-----------+
    3 rows in set (0.00 sec)
  4. 从服务器上修改change master to,并启用slave

    MariaDB [(none)]> CHANGE MASTER TO 
        -> MASTER_HOST=‘192.168.205.17‘, 
        -> MASTER_USER=‘repluser‘, 
        -> MASTER_PASSWORD=‘centos‘, 
        -> MASTER_PORT=3306,
        -> MASTER_LOG_FILE=‘bin.000003‘, 
        -> MASTER_LOG_POS=406; 
    Query OK, 0 rows affected (0.01 sec)
    
    MariaDB [(none)]> start slave;
    Query OK, 0 rows affected (0.00 sec)
    
    MariaDB [(none)]> show slave status\G
    *************************** 1. row ***************************
                   Slave_IO_State: Waiting for master to send event
                      Master_Host: 192.168.205.17
                      Master_User: repluser
                      Master_Port: 3306
                    Connect_Retry: 60
                  Master_Log_File: bin.000003
              Read_Master_Log_Pos: 406
                   Relay_Log_File: mariadb-relay-bin.000002
                    Relay_Log_Pos: 523
            Relay_Master_Log_File: bin.000003
                 Slave_IO_Running: Yes
                Slave_SQL_Running: Yes
  5. 要启用主从的半同步复制需要安装一个插件
    [root@centos7 data]#rpm -ql mariadb-server
    /usr/lib64/mysql/plugin/semisync_master.so
    /usr/lib64/mysql/plugin/semisync_slave.so
  6. 在数据库中可以查看那些插件安装
    MariaDB [(none)]> show plugins;
  7. 在主服务器上安装插件
    MariaDB [(none)]> install plugin rpl_semi_sync_master soname ‘semisync_master.so‘;
    Query OK, 0 rows affected (0.00 sec)
    MariaDB [(none)]> show plugins;
    …
    | rpl_semi_sync_master           | ACTIVE   | REPLICATION        | semisync_master.so | GPL     |
    +--------------------------------+----------+--------------------+--------------------+---------+
    43 rows in set (0.00 sec)
  8. 查看半同步的状态
    MariaDB [(none)]> show global variables like ‘%semi%‘ ;
    +------------------------------------+-------+
    | Variable_name                      | Value |
    +------------------------------------+-------+
    | rpl_semi_sync_master_enabled       | OFF   | #半同步默认off
    | rpl_semi_sync_master_timeout       | 10000 | #超时毫秒,10秒
    | rpl_semi_sync_master_trace_level   | 32    |
    | rpl_semi_sync_master_wait_no_slave | ON    |
    +------------------------------------+-------+
    4 rows in set (0.00 sec)
  9. 启用半同步
    MariaDB [(none)]> set global rpl_semi_sync_master_enabled=on;
    Query OK, 0 rows affected (0.00 sec)
  10. 查看半同步状态信息
    MariaDB [(none)]> show global status like ‘%semi%‘;
    +--------------------------------------------+-------+
    | Variable_name                              | Value |
    +--------------------------------------------+-------+
    | Rpl_semi_sync_master_clients               | 0     |
    | Rpl_semi_sync_master_net_avg_wait_time     | 0     |
    | Rpl_semi_sync_master_net_wait_time         | 0     |
    | Rpl_semi_sync_master_net_waits             | 0     |
    | Rpl_semi_sync_master_no_times              | 0     |
    | Rpl_semi_sync_master_no_tx                 | 0     |
    | Rpl_semi_sync_master_status                | ON    |
    | Rpl_semi_sync_master_timefunc_failures     | 0     |
    | Rpl_semi_sync_master_tx_avg_wait_time      | 0     |
    | Rpl_semi_sync_master_tx_wait_time          | 0     |
    | Rpl_semi_sync_master_tx_waits              | 0     |
    | Rpl_semi_sync_master_wait_pos_backtraverse | 0     |
    | Rpl_semi_sync_master_wait_sessions         | 0     |
    | Rpl_semi_sync_master_yes_tx                | 0     |
    +--------------------------------------------+-------+
    14 rows in set (0.00 sec)
  11. 在所有的从节点安装slave semi插件;
    MariaDB [(none)]>  install plugin rpl_semi_sync_slave soname ‘semisync_slave.so‘;       
    Query OK, 0 rows affected (0.00 sec)
    MariaDB [(none)]> show plugins;
    …
    | rpl_semi_sync_slave            | ACTIVE   | REPLICATION        | semisync_slave.so | GPL     |
    +--------------------------------+----------+--------------------+-------------------+---------+
    43 rows in set (0.00 sec)
  12. 查看slave的半同步状态,并启用,并需要重新启动线程,再查看半同步状态是on才可以

    MariaDB [(none)]> show global variables like ‘%semi%‘;
    +---------------------------------+-------+
    | Variable_name                   | Value |
    +---------------------------------+-------+
    | rpl_semi_sync_slave_enabled     | OFF   |
    | rpl_semi_sync_slave_trace_level | 32    |
    +---------------------------------+-------+
    2 rows in set (0.00 sec)
    MariaDB [(none)]> set global rpl_semi_sync_slave_enabled=on; 
    Query OK, 0 rows affected (0.00 sec)
    MariaDB [(none)]> show global variables like ‘%semi%‘;      
    +---------------------------------+-------+
    | Variable_name                   | Value |
    +---------------------------------+-------+
    | rpl_semi_sync_slave_enabled     | ON    |
    | rpl_semi_sync_slave_trace_level | 32    |
    +---------------------------------+-------+
    2 rows in set (0.00 sec)
    MariaDB [(none)]> stop slave;
    Query OK, 0 rows affected (0.00 sec)
    
    MariaDB [(none)]> start slave;
    Query OK, 0 rows affected (0.00 sec)
    MariaDB [(none)]> show global status like ‘%semi%‘;  
    +----------------------------+-------+
    | Variable_name              | Value |
    +----------------------------+-------+
    | Rpl_semi_sync_slave_status | ON    |
    +----------------------------+-------+
    1 row in set (0.00 sec)
  13. 此时查看主节点的状态
    MariaDB [(none)]> show global status like ‘%semi%‘;
    +--------------------------------------------+-------+
    | Variable_name                              | Value |
    +--------------------------------------------+-------+
    | Rpl_semi_sync_master_clients               | 2     |
    | Rpl_semi_sync_master_net_avg_wait_time     | 0     |
    | Rpl_semi_sync_master_net_wait_time         | 0     |
    | Rpl_semi_sync_master_net_waits             | 0     |
    | Rpl_semi_sync_master_no_times              | 0     |
    | Rpl_semi_sync_master_no_tx                 | 0     |
    | Rpl_semi_sync_master_status                | ON    |
    | Rpl_semi_sync_master_timefunc_failures     | 0     |
    | Rpl_semi_sync_master_tx_avg_wait_time      | 0     |
    | Rpl_semi_sync_master_tx_wait_time          | 0     |
    | Rpl_semi_sync_master_tx_waits              | 0     |
    | Rpl_semi_sync_master_wait_pos_backtraverse | 0     |
    | Rpl_semi_sync_master_wait_sessions         | 0     |
    | Rpl_semi_sync_master_yes_tx                | 0     |
    +--------------------------------------------+-------+
    14 rows in set (0.00 sec)
  14. 测试,在主节点上创建一个库
    MariaDB [(none)]> create database db1;
    Query OK, 1 row affected (0.00 sec)
  15. 在从节点上可以看到同步
    MariaDB [(none)]> show databases;     
    +--------------------+
    | Database           |
    +--------------------+
    | information_schema |
    | db1                |
    | mysql              |
    | performance_schema |
    | test               |
    +--------------------+
    5 rows in set (0.00 sec)
  16. 此进我们把slave1停掉,在主节点创建数据库,显示可以成功, 只会复制到slave2节点上
    [root@slave1 ~]#systemctl stop mariadb
    MariaDB [(none)]> create database db2; 
    Query OK, 1 row affected (0.01 sec)
    MariaDB [(none)]> show databases;
    +--------------------+
    | Database           |
    +--------------------+
    | information_schema |
    | db1                |
    | db2                |
    | mysql              |
    | performance_schema |
    | test               |
    +--------------------+
    6 rows in set (0.00 sec)
  17. 如果全部停掉从节点,再从主节点创建数据库,会等10秒才会显示成功
    [root@slave2 ~]#systemctl stop mariadb;
    MariaDB [(none)]> create database db3;
    Query OK, 1 row affected (10.00 sec)
  18. 将两个服务器再重新启动后,查看数据也会同步
    [root@slave1 ~]#systemctl start mariadb 
    MariaDB [(none)]> show databases;
    +--------------------+
    | Database           |
    +--------------------+
    | information_schema |
    | db1                |
    | db2                |
    | db3                |
    | mysql              |
    | performance_schema |
    | test               |
    +--------------------+
    7 rows in set (0.00 sec)

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