What's using all of my memory?

[thehemi]

I had a small server with 512MB of physical memory.
It was eventually swapping several hundred MB, so I
had it upgraded to 1.5GB of physical memory. Now it
is using all of that and swapping a couple hundred KB.

Although, checking through my other systems, I see
that every one of them maxes out the physical RAM
and uses a tiny bit of swap. I guess that's normal?

That said, is there any way to see WHERE all of the
memory is going? Perhaps to see how much certain
applications or services might be using?

If the OS wants to "cache" a bunch of data into RAM,
that's fine, but I'm still curious how much actual RAM
is being used by the apps and services, so that I can
tell when they're getting close to max'ing out...

[reiko]

Buddy U can use "TOP" command to get info about the resource utilization of each application and services running currently.

[thehemi]

Buddy U can use "TOP" command to get info about the resource utilization of each application and services running currently.

What exactly am I going to look for under the top output?
When I add up the %MEM results... I'm only showing 19%.

[daark.child]

Another command thay may help is "free". The output will show how much ram is being used and how much of it is simply cached memory that will be free to use when needed.

[thehemi]

Another command thay may help is "free". The output will show how much ram is being used and how much of it is simply cached memory that will be free to use when needed.

Nice, I think that gives me some useful information.

total used free shared buffers cached
Mem: 1539528 1497136 42392 0 52312 1226604
-/+ buffers/cache: 218220 1321308

The 1.5GB total minus 1.2GB cached comes out to roughly 20%.
Ok, that is making a little more sense, and something I can see.

Thanks for your help!