Linux/cache/hdparm

Links
http://www.techpulp.com/blog/2010/01/how-to-free-cached-memory-and-dirty-pages-in-linux/

To free page cache:

[root@techpulp ~]# echo 1 > /proc/sys/vm/drop_caches

To free dentries and inodes:

[root@techpulp ~]# echo 2 > /proc/sys/vm/drop_caches

To free page cache, dentries and inodes:

[root@techpulp ~]# echo 3 > /proc/sys/vm/drop_caches

hdparm -I /dev/sda