[mrtg] MRTG vs. Cricket

[McDonald, Dan]

On Fri, 2009-01-30 at 15:05 -0800, Patrick Topping wrote:
> I have been polling the 64-bit counters from the beginning.  Below is a 
> sample from the CFG file:
> 
> Target[xxx.xxx.xxx_TenGigabitEthernet10_4]: 
> \TenGigabitEthernet10/4:XXXXX at XXXXX:::::2
> 
> I know that the graphs are off because I still have Cricket graphing the 
> same devices as MRTG.  I left Cricket in place while I migrated 
> everything over to MRTG.  When I look at the graphs on the same 10-gig 
> interface and look at the actual 10-gig interface on the router, the 
> Cricket graphs seem be more accurate.

so, you are polling the locIfOutBitsSec and locIfInBitsSec variables
with Cricket?  Those would match the "show interface" values on the
router, but they are not accurate.  They are exponentially weighted to
give preference to the last 15 seconds of traffic, rather than a
straight-line average of the number of bytes actually transmitted.

The ifHCInOctets and ifHCOutOctets will give you statistically better
information over the long term.  And precise numbers is you want totals.

If you want to compare, just create a separate target for the locIf{In|
Out}BitsSec OIDs, set options[]: guage, and see if those match
precisely.


> 
> I have changed the cron from running every 5 minutes to running every 
> minute.  I will see how well this does and update the group from there.  
> Thanks for all the help so far.
> 
> -Patrick
> 
> ------------------------------------
> 
> Sean Cheesman wrote:
> > Are you polling v2?  v2 uses 64 bit counters, versus 32 bit v1, which 
> > isn't enough for anything over like 600Mbps (I don't recall the actual 
> > rollover point).
> > ------------------------------------------------------------------------
> > *From:* mrtg-bounces at lists.oetiker.ch [mrtg-bounces at lists.oetiker.ch] 
> > On Behalf Of Patrick Topping [ptopping at pobox.com]
> > *Sent:* Friday, January 30, 2009 12:33 PM
> > *To:* 'mrtg at lists.oetiker.ch'
> > *Subject:* [mrtg] MRTG vs. Cricket
> >
> > I am hoping someone can help me out with this issue I am having.....  I
> > am working on migrating from Cricket to MRTG.  So far so good except
> > that the Cricket graphs are pretty spot on for a 5 minute interval while
> > the MRTG graphs are anywhere from 600 Mbps to 1 Gbps off at peak time.
> > For example, I have a 10-gig circuit that runs roughly at 7 Gbps a peak
> > time.  Cricket graphs it damn near spot on.  MRTG is off by almost a
> > full gig.
> >
> > I have checked the cron jobs and both services are running every 5
> > minutes.  They are synced to NTP and the clocks are not off so they are
> > both seeing the exact same data.  I have set up my CFG files to use the
> > 64 bit counters.
> >
> > I have Googled for answers but not a lot out there on this topic.  I am
> > hoping this is something small I have missed and can easily be fixed.
> > Any ideas?  Thanks in advance.
> >
> > -Patrick
> >
> >
> > _______________________________________________
> > mrtg mailing list
> > mrtg at lists.oetiker.ch
> > https://lists.oetiker.ch/cgi-bin/listinfo/mrtg
> 
> _______________________________________________
> mrtg mailing list
> mrtg at lists.oetiker.ch
> https://lists.oetiker.ch/cgi-bin/listinfo/mrtg
-- 
Daniel J McDonald, CCIE #2495, CISSP #78281, CNX
Austin Energy
http://www.austinenergy.com

-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 197 bytes
Desc: This is a digitally signed message part
Url : http://lists.oetiker.ch/pipermail/mrtg/attachments/20090130/2afe058b/attachment.bin