编辑配置 - Master
[root@localhost /]# vi /etc/my.cnf
log-bin=master-bin
log-slave-updates = true
server-id = 1
重启服务
[root@localhost /]# systemctl reload mysqld
创建并授权同步账号
mysql> grant replication slave on *.* to 'myslave'@'192.168.242.188' identified by '123456';
mysql> flush privileges;
mysql> show master status;
+------------------+----------+--------------+------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000014 | 107 | | |
+------------------+----------+--------------+------------------+
1 row in set (0.00 sec)
编辑配置 - Slave
[root@localhost data]# vi /etc/my.cnf
server-id = 2
srelay-log=relay-log-bin
relay-log-index=slave-relay-bin-index
重启服务
[root@localhost /]# systemctl reload mysqld
开启 Slave配置
mysql> change master to master_host='192.168.242.185', master_user='myslave', master_password='123456', master_log_file='mysql-bin.000014', master_log_pos=107;
mysql> start slave;
mysql> show slave status\G
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
问题：
mysql> change master to master_host='192.168.242.185', master_user='myslave', master_password='123456', master_log_file='mysql-bin.000014', master_log_pos=107;
ERROR 1201 (HY000): Could not initialize master info structure; more error messages can be found in the MySQL error log
解决：
mysql> slave stop;
mysql> reset slave
mysql> change master to master_host='192.168.242.185', master_user='myslave', master_password='123456', master_log_file='mysql-bin.000014', master_log_pos=107;
mysql> slave start;
主从好处
- 分摊服务器压力，提高机器系统的处理效率
- 增加冗余，提高服务可用性
原理
依赖二进制日志bin-log，其记录了引起数据库变化的语句（Insert、update、delete、create table）
Scale-up 与 Scale-out
Scale-out 是指Application在水平方向上的扩展，即当添加更多机器 时，应用可以利用这些资源来提升自己的效率
Scale-up 是指Application在垂直方向上的扩展，即当机器添加更多的CPU、内存等资源时，应该可以充分利用这些资源来提升其效率