在现代企业中，数据显得尤为重要，而存储数据的数据库选择又五花八门，但无论是何种数据库，均存在着一种隐患。
想几个问题：
主从复制步骤：
主从复制配置步骤：
环境说明：
| 数据库角色 | IP | 应用与系统版本 | 有无数据 |
|---|---|---|---|
| 主数据库 | 172.16.12.128 | centos7/redhat7 mysql-5.7 |
有数据 |
| 从数据库 | 172.16.12.129 | centos7/redhat7 mysql-5.7 |
无数据 |
分别在主从两台服务器上安装mysql-5.7版本
为确保从数据库与主数据库里的数据一样，先全备主数据库并还原到从数据库中
//先查看主库有哪些库
[root@localhost ~]# mysql -uroot -pwangqing123! -e ‘show databases;‘
mysql: [Warning] Using a password on the command line interface can be insecure.
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| student |
| sys |
| teacher |
+--------------------+
//再查看从库有哪些库
[root@localhost ~]# mysql -uroot -pwangqing123! -e ‘show databases;‘
mysql: [Warning] Using a password on the command line interface can be insecure.
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
+--------------------+
//全备主库
//全备主库时需要另开一个终端，给数据库加上读锁，避免在备份期间有其他人在写入导致数据不一致
mysql> FLUSH TABLES WITH READ LOCK;
Query OK, 0 rows affected (0.00 sec)
//此锁表的终端必须在备份完成以后才能退出
//备份主库并将备份文件传送到从库
[root@localhost ~]# mysqldump -uroot -pwangqing123! --all-databases > /opt/all-201808191200.sql
mysqldump: [Warning] Using a password on the command line interface can be insecure.
[root@localhost ~]# ls /opt/
all-201808191200.sql
[root@localhost ~]# scp /opt/all-201808191200.sql root@172.16.12.129:/opt/
root@172.16.12.129‘s password:
all-201808191200.sql 100% 786KB 10.6MB/s 00:00
//解除主库的锁表状态，直接退出交互式界面即可
mysql> quit
Bye
//在从库上恢复主库的备份并查看从库有哪些库，确保与主库一致
[root@localhost ~]# mysql -uroot -pwangqing123! < /opt/all-201808191200.sql
mysql: [Warning] Using a password on the command line interface can be insecure.
[root@localhost ~]# mysql -uroot -pwangqing123! -e ‘show databases;‘
mysql: [Warning] Using a password on the command line interface can be insecure.
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| student |
| sys |
| teacher |
+--------------------+
在主上授权给从
MariaDB [(none)]> grant replication slave on *.* to ‘repl‘@‘192.168.23.133‘ identified by ‘repl123‘;
Query OK, 0 rows affected (0.000 sec)
MariaDB [(none)]> flush privileges;
Query OK, 0 rows affected (0.000 sec)
在从上链接主
[root@localhost ~]# mysql -urepl -prepl123 -h192.168.23.132
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MariaDB connection id is 9
Server version: 10.3.17-MariaDB MariaDB Server
Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.
Type ‘help;‘ or ‘\h‘ for help. Type ‘\c‘ to clear the current input statement.
MariaDB [(none)]>
[root@localhost ~]# vim /etc/my.cnf
//在[mysqld]这段的后面加上如下内容
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
log-bin=mysql-bin //启用binlog日志
server-id=10 //数据库服务器唯一标识符，主库的server-id值必须比从库的大
symbolic-links=0
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid
//重启mysql服务
[root@localhost ~]# systemctl restart mysqld
[root@localhost ~]# ss -antl
State Recv-Q Send-Q Local Address:Port Peer Address:Port
LISTEN 0 128 *:22 *:*
LISTEN 0 100 127.0.0.1:25 *:*
LISTEN 0 128 :::22 :::*
LISTEN 0 100 ::1:25 :::*
LISTEN 0 80 :::3306 :::*
//查看主库的状态
MariaDB [(none)]> show master status;
+------------------+----------+--------------+------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000001 | 328 | | |
+------------------+----------+--------------+------------------+
1 row in set (0.000 sec)
[root@localhost ~]# vim /etc/my.cnf
//添加如下内容
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
server-id=20 //设置从库的唯一标识符，从库的server-id值必须大于主库的该值
relay-log=myrelay //启用中继日志relay-log
symbolic-links=0
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid
//重启从库的mysql服务
[root@localhost ~]# systemctl restart mysqld
[root@localhost ~]# ss -antl
State Recv-Q Send-Q Local Address:Port Peer Address:Port
LISTEN 0 128 *:22 *:*
LISTEN 0 100 127.0.0.1:25 *:*
LISTEN 0 128 :::22 :::*
LISTEN 0 100 ::1:25 :::*
LISTEN 0 80 :::3306 :::*
//配置并启动主从复制
MariaDB [(none)]> change master to master_host=‘192.168.23.132‘,master_user=‘repl‘,master_password=‘repl123‘,master_log_file=‘mysql-bin.000001‘,master_log_pos=328;
Query OK, 0 rows affected (0.003 sec)
MariaDB [(none)]> start slave;
Query OK, 0 rows affected (0.001 sec)
MariaDB [(none)]> show slave status\G;
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.23.132
Master_User: repl
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000002
Read_Master_Log_Pos: 328
Relay_Log_File: mariadb-relay-bin.000003
Relay_Log_Pos: 627
Relay_Master_Log_File: mysql-bin.000002
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
MariaDB [school]> select * from student;
+----+------+------+-------+
| id | name | age | score |
+----+------+------+-------+
| 1 | aaa | 14 | 80 |
| 2 | bbb | 15 | 76 |
| 3 | ccc | 16 | 88 |
| 4 | ddd | 17 | 99 |
+----+------+------+-------+
4 rows in set (0.000 sec)
MariaDB [(none)]> select * from school.student;
+----+------+------+-------+
| id | name | age | score |
+----+------+------+-------+
| 1 | aaa | 14 | 80 |
| 2 | bbb | 15 | 76 |
| 3 | ccc | 16 | 88 |
| 4 | ddd | 17 | 99 |
+----+------+------+-------+
4 rows in set (0.000 sec)
原文：https://www.cnblogs.com/Ycqifei/p/14224541.html