[smokeping-users] Smokeping duplicate and possibly false packet loss bug

[Vinny Abello]

I'm observing what I believe is a bug, not only on my installation, but even on the demo page for Smokeping.

When I see a 1/20 loss, it ALWAYS shows up twice in two consecutive 5 minute intervals. The chance of loosing a packet in one five minute period followed by another loss in the next 5 minute period every single time is not likely. I thought this was just an issue on my network, but NO other tools can detect any loss where Smokeping keeps showing this loss randomly. The loss never happens at the same time on different graphs going through the same network path. They are always random and ALWAYS happen consecutively. I see the EXACT same pattern on the Smokeping demo web page. I can't quantify the loss measurements that smokeping is seeing with anything else and can't believe there is as much loss as it claims there is on various installations across different networks I have seen.

I'm looking for a way to prove this. I suspect it's some sort of bug that fping is generating a value that cannot be input into the RRD database so it ends up as a null value and shows as loss. I'm not sure about the duplicate consecutive occurrences of it, but I believe it's related.

How can this be debugged, proven or disproven? I'm not an RRDTool guru but am really perplexed by the data Smokeping is showing.

I think this has only happened in more recent versions of Smokeping. When I first started running it, I never saw these patterns. Either an updated version of Smokeping is causing this or possibly fping, but I have also seen the same pattern with two consecutive 1/20 loss values on other monitor types as well.

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Vinny Abello
Network Engineer
Server Management
vinny at tellurian.com
(973)300-9211 x 125
(973)940-6125 (Direct)
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