Re: Getting frequent "NaN" gaps in graphs, yet data is being retrieved ok

Thanks, and thank you to the people who replied off list as well.

The solution was as simple as adding "snmp-version = 3" to the interfaces 
file for the routers and switches that have gigabit interfaces.

Thanks,
Andy

On Thu, 31 Mar 2011, Clarke Morledge wrote:

> Andy,
> 
> Most probably, you are using 32-bit counters in your SNMP sources, and the
> counters are wrapping around.  When that happens, you'll get negative results
> in your deltas, which is what gives you the NaN values in your graphs.
> 
> I started running into this a few years ago once we started to put some load
> on our gigabit links.  Moving to using 64-bit counters (where possible) will
> fix this.  Just remember that you'll probably have to graduate from SNMPv1 to
> SNMPv2c or 3 to get the 64-bit support in your MIBs.
> 
> Clarke Morledge
> College of William and Mary
> Information Technology - Network Engineering
> Jones Hall (Room 18)
> Williamsburg VA 23187
> 
> On Thu, 31 Mar 2011, Andy Dills wrote:
> 
> > 
> > I've been using cricket for around a decade.
> > 
> > In the last few years, we've grown to the gigabit ethernet level. Since
> > then, we've been getting strange gaps in our graphs, with NaN listed as
> > the current value if you look at the graph when the gap is occuring. It
> > doesn't seem to be based on a traffic level threshhold...I'll see valid
> > data displayed at times that are higher usage than the traffic rates when
> > the data is NaN.
> > 
> > Whenever I run a manual collector, the data is being retrieved fine. I
> > can't figure out why the data isn't being displayed properly, and I'm not
> > able to think of a way to troubleshoot this further. I've tried specifying
> > the speeds of the interfaces, and I've even tried doing a fresh install on
> > a much more modern server (as the server cricket has been on since 2004 is
> > still chugging along, and producing graphs a bit more slowly than it
> > should).
> > 
> > Any suggestions?
> > 
> > Thanks,
> > Andy
> > 
> > ---
> > Andy Dills
> > Xecunet, Inc.
> > www.xecu.net
> > 301-682-9972
> > ---
> 

---
Andy Dills
Xecunet, Inc.
www.xecu.net
301-682-9972
---

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