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Hi All,

I have a rrdtool program to query the snmp and graph the network performance graph.

However , I find that those network port with huge usage (Let say more than 600Mb) , and then the graph can not reflect the actual usage of the network port. But those network port with normal usage are working fine.

I read this page (http://www.mrtg.org/rrdtool/tut/rrdtutorial.en.html#___top). I wild guess that the problem may related to Counter Wraps mentioned in the page. Any suggestion or comment on it?

Thanks,<br>
frankie

<hr>

Tobi:

rrdtool does recognize counter wraps in 32 and 64bit counters, but if a counter wraps multiple times between update intervals, then rrdtool will not be able to give accurate results anymore ... to prevent this:

* Use 64bit counters
* Read counters frequently
* If the counter wraps at odd times, use the DERIVE ds type with a minimum value of 0. This will cause counter wraps to cause 'unknowns' to be logged.

cheers<br>
tobi