MySQL数据库主从复制

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。

基础环境设置

防火墙和上下文

#主从
[root@slave ~]# systemctl disable --now firewalld
Removed /etc/systemd/system/multi-user.target.wants/firewalld.service.
Removed /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.
[root@slave ~]# getenforce
Enforcing
[root@slave ~]# sed -i 's/SELINUX=enforcing/SELINUX=disabled/' /etc/selinux/config
[root@slave ~]# setenforce 0

网络对时

#主从
[root@localhost ~]# cat /etc/chrony.conf | grep -Ev '^$|#'
server ntp.aliyun.com iburst ###添加或修改
driftfile /var/lib/chrony/drift
makestep 1.0 3
rtcsync
keyfile /etc/chrony.keys
leapsectz right/UTC
logdir /var/log/chrony 
[root@master ~]# timedatectl set-timezone Asia/Shanghai
[root@master ~]# date
2025年 07月 05日 星期六 17:18:20 CST

主从配置

主配置

#创建一个从可以登录的账户，并赋予权限
mysql> create user 'slave'@'192.168.157.%' identified by '1230';
Query OK, 0 rows affected (0.01 sec)
#因为要同步所有数据，所以给全部权限
mysql> grant all on *.* to 'slave'@'192.168.157.%';
Query OK, 0 rows affected (0.00 sec)
#主服务文件配置
#屏蔽原有日志文件，新建日志文件，设置id值 
[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=101 #主从必须不一样 
#重启MySQL服务
[root@master ~]# systemctl restart mysqld
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000003 |      157 |              |                  |                   |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)
#注意：查看位置完毕后，不要对master做insert、update、delete、create、drop等操作！！！

从配置

#修改配置文件
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  1
server-id=202  #与主配置要不一样    1
#进入MySQL 指向主服务器
[root@slave mysql]# mysql
mysql> change master to master_host='192.168.157.150',master_user='slave',master_password='1230',master_log_file='mysqlbin.000003',master_log_pos=157;
#验证
mysql> start slave;
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> show slave status\G;
*************************** 1. row ***************************
               Slave_IO_State: Waiting for source to send event
                  Master_Host: 192.168.157.150
                  Master_User: slave
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000003
          Read_Master_Log_Pos: 157
               Relay_Log_File: slave-relay-bin.000002
                Relay_Log_Pos: 326
        Relay_Master_Log_File: mysql-bin.000003
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes
              Replicate_Do_DB: 
          Replicate_Ignore_DB: 
           Replicate_Do_Table: 
       Replicate_Ignore_Table: 
      Replicate_Wild_Do_Table: 
  Replicate_Wild_Ignore_Table: 
                   Last_Errno: 0
                   Last_Error: 
                 Skip_Counter: 0
          Exec_Master_Log_Pos: 157
              Relay_Log_Space: 536
              Until_Condition: None
               Until_Log_File: 
                Until_Log_Pos: 0
           Master_SSL_Allowed: No
           Master_SSL_CA_File: 
           Master_SSL_CA_Path: 
              Master_SSL_Cert: 
            Master_SSL_Cipher: 
               Master_SSL_Key: 
        Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
                Last_IO_Errno: 0
                Last_IO_Error: 
               Last_SQL_Errno: 0
               Last_SQL_Error: 
  Replicate_Ignore_Server_Ids: 
             Master_Server_Id: 101
                  Master_UUID: f2a6f311-51cb-11f0-bd56-000c299bfda5
             Master_Info_File: mysql.slave_master_info
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: Replica has read all relay log; waiting for more updates
           Master_Retry_Count: 86400
                  Master_Bind: 
      Last_IO_Error_Timestamp: 
     Last_SQL_Error_Timestamp: 
               Master_SSL_Crl: 
           Master_SSL_Crlpath: 
           Retrieved_Gtid_Set: 
            Executed_Gtid_Set: 
                Auto_Position: 0
         Replicate_Rewrite_DB: 
                 Channel_Name: 
           Master_TLS_Version: 
       Master_public_key_path: 
        Get_master_public_key: 0
            Network_Namespace: 

测试

#从
mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
4 rows in set (0.01 sec)
#主
mysql> create database slave;
Query OK, 1 row affected (0.01 sec)
#从
mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| slave              |
| sys                |
+--------------------+
5 rows in set (0.01 sec)

重复

reset replica;
##用于重置SQL线程对relay log的重放记录！！