[root@edc01 ~]# free -m
total used free shared buffers cached
Mem: 15951 15779 171 0 300 4223
-/+ buffers/cache: 11256 4694
Swap: 0 0 0
[root@edc01 ~]# cat /proc/sys/vm/drop_caches
0
[root@edc01 ~]# sync
[root@edc01 ~]# echo 3 > /proc/sys/vm/drop_caches
[root@edc01 ~]# free -m
total used free shared buffers cached
Mem: 15951 11014 4936 0 0 36
-/+ buffers/cache: 10978 4973
Swap: 0 0 0
[root@edc01 ~]# free -m
total used free shared buffers cached
Mem: 15951 11017 4934 0 3 36
-/+ buffers/cache: 10977 4974
Swap: 0 0 0
[root@edc01 ~]# cat /proc/sys/vm/drop_caches
3