最近频繁接到数据库服务器磁盘空间不足的告警，实际上数据库文件本身不大，主要是半年多累积的binary logs大，尤其是有主从配置的DB。查看了很多资料，总结了一下常用的专门针对binary logs的mysql命令：
1. Binary logs 位置：
1）查看/etc/my.cnf (Windows下为my.ini）, 例如：
log_bin=/var/mydb/bin-log
如果该设置没带路径，就放在datadir=/var/lib/mysql 下
2） 到数据库查看是否开启binary log 功能：
mysql> show variables like 'log_bin';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| log_bin | ON |
+---------------+-------+
1 row in set (0.00 sec)
mysql> show variables like 'log_bin';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| log_bin | OFF |
+---------------+-------+
1 row in set (0.01 sec)
如果是OFF就没有以下工作了：）
2. 查看当前工作的logfile名及大小： show binary logs /show master logs;
mysql> show binary logs;
+-----------------+-----------+
| Log_name | File_size |
+-----------------+-----------+
| bin-log.000011 | 148329 |
+-----------------+-----------+
mysql> show master logs;
+-----------------+-----------+
| Log_name | File_size |
+-----------------+-----------+
| bin-log.000011 | 148329 |
+-----------------+-----------+
mysql> show binary logs;
ERROR 1381 (HY000): You are not using binary logging ###没有开启binary logs
3. 清除所有binary logs;
1)
mysql> show master logs;
+-----------------+-----------+
| Log_name | File_size |
+-----------------+-----------+
| log-bin.000001 | 259548 |
| log-bin.000002 | 37200 |
| log-bin.000003 | 74219 |
+-----------------+-----------+
3 rows in set (0.00 sec)
mysql> reset master; (在slave上，用reset slave，之前应stop slave，之后再start slave）
Query OK, 0 rows affected (0.00 sec)
mysql> show master logs;
+-----------------+-----------+
| Log_name | File_size |
+-----------------+-----------+
| log-bin.000001 | 98 |
+-----------------+-----------+
1 row in set (0.00 sec)
4. 清除指定部分logs：
mysql>purge binary logs to 'log-bin.000012';
将log-bin.000012之前的binary logs清掉；
mysql>purge binary logs before '2011-05-28 12:05:38';
将指定时间之前的binary logs清掉；
5.查看当前binary log的情况：
mysql>show master status;
6. 查看binary logs的内容：
mysql>show binlog events;
命令行下：
#mysqlbinlog /var/log/mysql/log-bin.000140; 或者
#mysqlbinlog --start-datetime='2011-07-01 00:00:00' --stop-datetime='2010-07-15 00:00:00' /var/log/mysql/log-bin.000020 > ./tmp.log
7. 在my.cnf/my.ini中设定binary logs回滚天数：
expire_logs_days = 7