Hi,
how to find out actual utilization of memory using sar -r in Linux, I understand Linux keep entire memory in cache/buffers.
I would like to know how to find out actual usage of memory
Look for anything that's not cache...
Linux is not unique in using "entire memory" in cache/buffers. I can't think of a major OS which doesn't. Empty memory sitting around doing nothing is a waste in a multitasking system.