[mrtg] Correct way to do Target math?

[Eric Brander]

On 7/24/07, Ray Van Dolson <rvandolson at esri.com> wrote:
> I'm trying to generate a graph using SNMP of actual memory used on a
> Linux system running Net-SNMP.  In theory:
>
>   memTotalReal.0 - memBuffer.0 - memCached.0 - memAvailReal.0
>
> Is the real memory available.


Are you sure about that? Why would subtracting memAVAILreal from
memTOTALreal equal the real memory available? Seems that would give
you memory in use. But then why subtract the buffer and cached?

Maybe I don't understand those counters but that just doesn't jive in
my brain. Also, are these really counters or are they gauges?