如果配置了log_bin参数，则需要配置expire_logs_days参数指定二进制日志保留时间，不然磁盘空间早晚会被日志占满的。如果之前没有配置，则配置步骤如下：
1、查看当前配置
(root@localhost)[(none)] show global variables like 'log_bin';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| log_bin | ON |
+---------------+-------+
1 row in set (0.02 sec)
(root@localhost)[(none)] show global variables like 'expire_logs_days';
+------------------+-------+
| Variable_name | Value |
+------------------+-------+
| expire_logs_days | 0 |
+------------------+-------+
1 row in set (0.00 sec)
(root@localhost)[(none)] show global variables like 'max_binlog_size';
+-----------------+------------+
| Variable_name | Value |
+-----------------+------------+
| max_binlog_size | 1073741824 |
+-----------------+------------+
1 row in set (0.00 sec)
(root@localhost)[(none)] show binary logs;
+------------------+-----------+
| Log_name | File_size |
+------------------+-----------+
| mysql-bin.000001 | 614 |
| mysql-bin.000002 | 1595 |
| mysql-bin.000003 | 445747850 |
+------------------+-----------+
3 rows in set (0.02 sec)
[root@dbrac16 ~]# ll /usr/local/mysql/data/mysql-bin*
-rw-r----- 1 mysql mysql 614 May 11 10:06 /usr/local/mysql/data/mysql-bin.000001
-rw-r----- 1 mysql mysql 1595 May 17 09:45 /usr/local/mysql/data/mysql-bin.000002
-rw-r----- 1 mysql mysql 445747850 May 19 14:28 /usr/local/mysql/data/mysql-bin.000003
-rw-r----- 1 mysql mysql 117 May 17 11:16 /usr/local/mysql/data/mysql-bin.index
2、查看slave状态
[root@dbrac17 ~]# mysql -uroot -p123456 -e "show slave status\G" | grep Master_Log_File
mysql: [Warning] Using a password on the command line interface can be insecure.
Master_Log_File: mysql-bin.000003
Relay_Master_Log_File: mysql-bin.000003
3、手动清除过期的日志
如果堆积的日志太多，可以先执行这一步，清理掉一部分日志。
(root@localhost)[(none)] purge master logs before '2017-05-17 00:00:00';
Query OK, 0 rows affected (0.15 sec)
(root@localhost)[(none)] show binary logs;
+------------------+-----------+
| Log_name | File_size |
+------------------+-----------+
| mysql-bin.000002 | 1595 |
| mysql-bin.000003 | 445747850 |
+------------------+-----------+
2 rows in set (0.00 sec)
4、配置参数
[root@dbrac16 ~]# cat /etc/my.cnf | grep expire_logs_days
expire_logs_days = 3
修改参数文件，设置日志保留3天，需要重启才能生效。
直接设置，立即生效。
(root@localhost)[(none)] set global expire_logs_days=3;
Query OK, 0 rows affected (0.00 sec)
触发过期日志清除操作。
(root@localhost)[(none)] flush logs;
Query OK, 0 rows affected (0.04 sec)
(root@localhost)[(none)] show binary logs;
+------------------+-----------+
| Log_name | File_size |
+------------------+-----------+
| mysql-bin.000003 | 445747897 |
| mysql-bin.000004 | 201 |
+------------------+-----------+
3 rows in set (0.00 sec)
