Am 03.05.2011 05:31, schrieb Pablo Cavero:
> Dear all,
> 
> I'm use snmp service and apps to check my SL 5.5 Servers, on real-time,
> with the software "What's Up 14.3" and I can check Ram, HDD,Networks and
> others.
> This work very fine, but I have diff. measures when check the free Ram
> on the ssh consoles, and use the classical tools, like "free" and "top".
> 
> When the snmp report  100% of CPU in use, the "top" command, report only
> 72% of CPU in use.
> What do you think about that??
> 

Top does not report a single value for CPU usage but several: us
(userspace), sy (kernel), ni (userspace with positive nice values), wa
(waiting) and so on.

I guess your reporting tool is accumulating us, sy and ni.

> About the Ram, I found this link:
> 
> http://www.rt-embedded.com/blog/archives/linux-memory-consumption/
> 
> What do you think about that??
>

The information there looks about correct. I get different output from
`free`, however:
            total       used       free     shared    buffers     cached
Mem:       3843684    3622932     220752          0      85184    995880
-/+ buffers/cache:    2541868    1301816
Swap:      6289412    1258920    5030492

Here, the second line without buffers and cache is interesting.

When using `top`, look at the RES column and for some applications that
make usage of shared memory, the SHR column. The link you provided
completely ignores that but in some cases, this usage can be significant.

Hope this helps,
Florian Philipp