目录
一、概述
1、master开启二进制日志记录
2、slave开启IO进程，从master中读取二进制日志并写入slave的中继日志
3、slave开启SQL进程，从中继日志中读取二进制日志并进行重放
4、最终，达到slave与master中数据一致的状态，我们称作为主从复制的过程。
二、基础环境设置
网络对时
MySQL主
[root@localhost ~]# timedatectl
Local time: 二 2025-10-14 20:30:03 CST
Universal time: 二 2025-10-14 12:30:03 UTC
RTC time: 二 2025-10-14 12:30:03
Time zone: Asia/Shanghai (CST, +0800)
System clock synchronized: yes
NTP service: active
RTC in local TZ: no
MySQL从
[root@localhost ~]# timedatectl
Local time: 二 2025-10-14 20:30:05 CST
Universal time: 二 2025-10-14 12:30:05 UTC
RTC time: 二 2025-10-14 12:30:05
Time zone: Asia/Shanghai (CST, +0800)
System clock synchronized: yes
NTP service: active
RTC in local TZ: no防火墙与SELinux
[root@localhost ~]# systemctl disable --now firewalld
[root@localhost ~]# setenforce 0三、配置主从复制
主服务配置
修改配置文件
[root@localhost ~]# vim /etc/my.cnf.d/mysql-server.cnf
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
log-error=/var/log/mysql/mysqld.log
pid-file=/run/mysqld/mysqld.pid
log-bin=mysql-bin
binlog_format="statement"
server-id=11
log-slave-updates=true
[root@localhost ~]# systemctl restart mysqld配置完成后生成二进制日志文件
[root@localhost ~]# cd /var/lib/mysql
[root@localhost mysql]# ls
auto.cnf ca-key.pem ib_buffer_pool mydb mysql.sock.lock public_key.pem
binlog.000001 ca.pem ibdata1 mysql mysql_upgrade_info server-cert.pem
binlog.000002 client-cert.pem ibtmp1 mysql-bin.000001 mysqlx.sock server-key.pem
binlog.000003 client-key.pem '#innodb_redo' mysql-bin.index mysqlx.sock.lock sys
binlog.000004 '#ib_16384_0.dblwr' '#innodb_temp' mysql.ibd performance_schema undo_001
binlog.index '#ib_16384_1.dblwr' jx mysql.sock private_key.pem undo_002创建主从同步用户
mysql> create user slave@'192.168.150.%' identified by '123.com';
Query OK, 0 rows affected (0.03 sec)赋予权限
mysql> grant all on *.* to 'slave'@'192.168.150.%';
Query OK, 0 rows affected (0.00 sec)密码插件修改
mysql> alter user 'slave'@'192.168.150.%' identified with mysql_native_password by '123.com';
Query OK, 0 rows affected (0.00 sec)
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000003 | 157 | | | |
+------------------+----------+--------------+------------------+-------------------+从服务器配置
修改配置文件
[root@localhost ~]# vim /etc/my.cnf.d/mysql-server.cnf
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
log-error=/var/log/mysql/mysqld.log
pid-file=/run/mysqld/mysqld.pid
relay-log-index=slave-bin.index
server-id=22
[root@localhost ~]# systemctl restart mysqld配置从服务器的所属主服务器
mysql> change master to master_host='192.168.150.3',master_user='slave',master_password='123.com',master_log_file='mysql-bin.000003',master_log_pos=157;
Query OK, 0 rows affected, 8 warnings (0.01 sec)启动slave，查看slave状态信息
mysql> start slave;
Query OK, 0 rows affected, 1 warning (0.15 sec)
mysql> show slave status\G;
*************************** 1. row ***************************
Slave_IO_State: Waiting for source to send event
Master_Host: 192.168.150.3
Master_User: slave
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000003
Read_Master_Log_Pos: 157
Relay_Log_File: localhost-relay-bin.000002
Relay_Log_Pos: 326
Relay_Master_Log_File: mysql-bin.000003
Slave_IO_Running: Yes
Slave_SQL_Running: Yes验证
MySQL主
mysql> create database jx1;
Query OK, 1 row affected (0.01 sec)
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| jx |
| jx1 |
| mydb |
| mysql |
| performance_schema |
| sys |
+--------------------+MySQL从
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| jx1 |
| mysql |
| performance_schema |
| sys |
+--------------------+主从复制常见问题
一般情况下，都与网络通信异常有关系。排查防火墙、物理网络连接等。二进制日志文件名或位置错误也会引起IO线程异常。
reset replica;
##用于重置SQL线程对relay log的重放记录！！