如果mysql配置文件中启用log-bin=mysql-bin参数，当mysql数据库出问题时可以通过这些二进制日志文件来恢复；但是大量的数据也会导致产生大量的mysql-bin二进制文件而占满硬盘空间；如果是主从模式这个是一定要有的，如果是单库的话这就可以不需要的
删除操作：最好不要直接rm删除这些文件,而是通过mysql命令去安全删除
使用reset master 命令就会清空这些二进制日志文件
[root@localhost ~]# mysql -uroot -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 20938493
Server version: 5.7.18-log MySQL Community Server (GPL)
Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> reset master;
Query OK, 0 rows affected (1.38 sec)
mysql> exit
Bye
当然我们也可以指定这些二进制日志文件保留的天数，修改配置文件重启mysql生效
vim /etc/my.cnf
···
log-bin = mysql-bin
#加上此参数
expire_logs_days = 7
···
