Hints/pointers on MRTG for non-traffic SNMP data?

Thu May 27 13:53:37 PDT 2004

Quoting David Wolfskill (david at catwhisker.org):
> MRTG is something I've not had occasion to deal with much before, and I
> have a requirement to add some graphs of data extracted via SNMP, but that
> are not actually "traffic counters" (if that makes any sense) to some
> existing MRTG graphs (that do show traffic counters).
> 
> I like to think I'm fairly good at operating Web search engines, but I'm
> a bit stuck here, and keep getting either "nothing" or a lot of
> not-obviously-relevant hits.
> 
> Hints or clues?  (Yes, I did look at www.mrtg.org.)
> 
> Oh, in case it matters, this is in a FreeBSD environment.

I've been using SNMP as a transport protocol for data for years.
Basically, net-snmp can watch mail, count users, give me memory
use information, etc.  With V3, it's secure enough to allow
an snmp-set to reboot the machine (strong auth/encryption).

perl/php/shell can get SNMP data and feed it to rrdtool quite nicely.

For reasons of experimentation, I've been using a PHP command line
for several scripts.  It speaks XML, LDAP, SNMP and GD quite nicely
with one binary (a bitch to build, but once built, more portable
than perl and 500 libs.  And "a bitch to build" is moot with /usr/ports/).

Some for loops and I read memory use data from 30 machines and throw it
into RRDTool.  I can then graph per machine or in agreggate (show me
the 15 web servers mem use on one picture).

As I said, I used php, but had it in perl and shell before this
last little test.

rrdtool is the successor to the graphing/storage part of
MRTG (same author), and FAR FAR more efficient.