[CentOS] Switch to measure traffic at IP level?

Les Mikesell lesmikesell at gmail.com
Fri Oct 23 15:57:33 UTC 2009


nate wrote:
> Neil Aggarwal wrote:
> 
>> I just need something that gives me a usage graph
>> at daily, weekly, and monthly intervals with a 95%
>> line.
> 
> Don't use RRD for billing 95% it will not be accurate
> as RRD averages values over time. I use rtg (not mrtg,
> but rtg) together with SNMP to get accurate 95% readings
> at the interface/port level.
> 
> sflow is also a sampling mechanism, but it is pretty
> accurate depending on the interval, you can see this
> site for accuracy on sflow:
> 
> http://www.sflow.org/packetSamplingBasics/index.htm
> 
> If your just using rrd for casual monitoring, no problem
> but if your using it for billing at 95% then be
> careful.

RRD stores a certain number of samples at their collected values, then as they 
age, averages them into larger and larger time values per sample, with the 
numbers of each set being configurable.  If you keep the raw samples for the 
time span of the calculation you should get accurate values.

-- 
   Les Mikesell
    lesmikesell at gmail.com



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