Clearing the disk Cache:Ubuntu

Clearing the disk cache

For experimentation, it's very convenient to be able to drop the disk cache. For this, we can use the special file /proc/sys/vm/drop_caches. By writing 3 to it, we can clear most of the disk cache:

$ free -m
                    total       used       free     shared    buffers     cached
Mem:          1504       1471         33              0           36           801
-/+ buffers/cache:        633        871
Swap:         2047             6      2041

$ echo 3 | sudo tee /proc/sys/vm/drop_caches 
3

$ free -m
                    total       used       free     shared    buffers     cached
Mem:          1504        763        741              0             0           134
-/+ buffers/cache:       629        875
Swap:         2047            6      2041

Notice how "buffers" and "cached" went down, free mem went up, and free+buffers/cache stayed the same.      

Collected from: http://www.linuxatemyram.com/play.html