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MySQL数据库如何实现主从复制

news 2025/10/16 6:12:30

一、概述

二、基础环境设置

网络对时

防火墙与SELinux

三、配置主从复制

主服务配置

从服务器配置

主从复制常见问题

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 ~]# timedatectlLocal time: 二 2025-10-14 20:30:03 CSTUniversal time: 二 2025-10-14 12:30:03 UTCRTC time: 二 2025-10-14 12:30:03Time zone: Asia/Shanghai (CST, +0800)
System clock synchronized: yesNTP service: activeRTC in local TZ: noMySQL从
[root@localhost ~]# timedatectlLocal time: 二 2025-10-14 20:30:05 CSTUniversal time: 二 2025-10-14 12:30:05 UTCRTC time: 二 2025-10-14 12:30:05Time zone: Asia/Shanghai (CST, +0800)
System clock synchronized: yesNTP service: activeRTC 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]# lsauto.cnf        ca-key.pem           ib_buffer_pool   mydb               mysql.sock.lock      public_key.pembinlog.000001   ca.pem               ibdata1          mysql              mysql_upgrade_info   server-cert.pembinlog.000002   client-cert.pem      ibtmp1           mysql-bin.000001   mysqlx.sock          server-key.pembinlog.000003   client-key.pem      '#innodb_redo'    mysql-bin.index    mysqlx.sock.lock     sysbinlog.000004  '#ib_16384_0.dblwr'  '#innodb_temp'    mysql.ibd          performance_schema   undo_001binlog.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 eventMaster_Host: 192.168.150.3Master_User: slaveMaster_Port: 3306Connect_Retry: 60Master_Log_File: mysql-bin.000003Read_Master_Log_Pos: 157Relay_Log_File: localhost-relay-bin.000002Relay_Log_Pos: 326Relay_Master_Log_File: mysql-bin.000003Slave_IO_Running: YesSlave_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                |
+--------------------+