开启MySQL binlog日志的服务器，如果不设置自动清理日志，默认binlog日志一直保留着，时间一长，服务器磁盘空间被binlog日志占满，导致MySQL数据库出错。
使用下面方法可以安全清理binlog日志
一、没有主从同步的情况下清理日志
mysql -uroot -p123456 -e 'PURGE MASTER LOGS BEFORE DATE_SUB( NOW( ),INTERVAL 5 DAY)';
#mysql 定时清理5天前的binlog
mysql -u root -p #进入mysql 控制台
reset master; #重置binlog
二、MySQL主从同步下安全清理binlog日志
1、mysql -u root -p #进入从服务器mysql控制台
show slave statusG; #检查从服务器正在读取哪个日志，有多个从服务器，选择时间最早的一个做为目标日志。
2、进入主服务器mysql控制台
show master log; #获得主服务器上的一系列日志
PURGE MASTER LOGS TO 'binlog.000058'; #删除binlog.000005之前的，不包括binlog.000058
PURGE MASTER LOGS BEFORE '2016-06-22 13:00:00'; #清除2016-06-22 13:00:00前binlog日志
PURGE MASTER LOGS BEFORE DATE_SUB( NOW( ), INTERVAL 3 DAY); #清除3天前binlog日志
三、设置自动清理MySQL binlog日志
vi /etc/my.cnf #编辑配置
expire_logs_days = 15 #自动删除15天前的日志。默认值为0，表示从不删除。
log-bin=mysql-bin #注释掉之后，会关闭binlog日志
binlog_format=mixed #注释掉之后，会关闭binlog日志
:wq! #保存退出
扩展阅读：
mysql> help purge;
Name: 'PURGE BINARY LOGS'
Description:
Syntax:
PURGE { BINARY | MASTER } LOGS
{ TO 'log_name' | BEFORE datetime_expr }
The binary log is a set of files that contain information about data
modifications made by the MySQL server. The log consists of a set of
binary log files, plus an index file (see
http://dev.mysql.com/doc/refman/5.5/en/binary-log.html).
The PURGE BINARY LOGS statement deletes all the binary log files listed
in the log index file prior to the specified log file name or date.
BINARY and MASTER are synonyms. Deleted log files also are removed from
the list recorded in the index file, so that the given log file becomes
the first in the list.
This statement has no effect if the server was not started with the
--log-bin option to enable binary logging.
URL: http://dev.mysql.com/doc/refman/5.5/en/purge-binary-logs.html
Examples:
PURGE BINARY LOGS TO 'mysql-bin.010';
PURGE BINARY LOGS BEFORE '2008-04-02 22:46:26';