greetings, I've been using RRD for a while now and am quite happy with it :) Recently I received a request from my employer to graph the latency and packetloss in our network. My first choice would be MRTG, but due to it's limitation to be able to graph/measure only 2 things at a time (leaving out max/min and any other things I'd like to graph/measure) and some problems with scaling it we probably won't use it.
So then the question becomes, RRD or build your own. I'd like to try RRD. But I have a few questions first that I'd hope to get an answer to: Let's say I have an RRD with a 5 second measurement interval. The measurement will take some time, but it'll be less than a second. So we'd be putting data in the RRD at time+0+measurement_time, time+5+measurement_time, etc.. Would then, a measurement_time of 0.3 (and hence insertion time of for instance time+5.3) be subjected to resampling, resulting in a measurement of (if the measurement was 0.1) (0.1/5.3)*5 = 0.94 ? Or, would the time+5.3 insertion time be too late for the step, and be taken as time+6, resulting in (0.1/6)*5=0.83 as measured value? I suspect both cases will be answered with "no". But then, how about this: The time needed to measure the latency is dependent on the latency itself.. So if for some weird reason the latency would rise above 1 second, the measurement would take more than 1 second. Therefore, the insertion time would be time+6.3 (for instance) with a measured value of 1.2 The RRD will therefore resample and show a value of (1.2/6.3)*5 = 0.95 If this is correct, is there any way around this ? (other than measuring every second, eliminating any resampling, but no longer allowing latency to be measured over 1 second and creating so much network traffic that it will influence the measurement) Otherwise I think RRD will be useless for measuring latency.. Thank you for all your answers, Itris -- Unsubscribe mailto:[EMAIL PROTECTED] Help mailto:[EMAIL PROTECTED] Archive http://www.ee.ethz.ch/~slist/rrd-users WebAdmin http://www.ee.ethz.ch/~slist/lsg2.cgi
