Linux下清空磁盘缓存

在HA部署中遇到这样子的问题，当客户需求中提到：日志硬盘大小，而机器一直都是在生成线上，由于空间有限，当把磁盘空间写满了，如何去清空旧日志呢？

 

 

If you're on OS X, the 'purge' command (part of the CHUD developer tools) will cause the disk caches to be purged. On Linux, with a 2.6.16 kernel or newer, 'echo 3 > /proc/sys/vm/drop_caches' will achieve the same effect. Another trick on Linux is to use a separate filesystem for the benchmark--if you perform a umount/mount cycle
after each run the kernel will drop any cached data that came from that filesystem.

两种方法：
echo 3 > /proc/sys/vm/drop_caches
umount /dev/sdx

参考：
http://www.gamedev.net/community/forums/topic.asp?topic_id=402069
http://blog.chinaunix.net/u/27173/showart_467689.html