perfSONAR User Q&A and Other Discussion

[Andrew Lake <>]

Hi,

A negative latency value means NTP is not synchronized. It does NOT mean 
latency is under a millisecond by itself. In real terms, it means a packet 
arrived to the destination before it was sent, which isn't possible unless 
the clocks are wrong. I would recommend correcting the clocks if at all 
possible rather than changing the thresholds.

That being said, the thresholds in maddash are completely configurable. Under 
the checks section you can adjust the "command" option with the thresholds 
you want. Changing the -c and -w options to something containg the negative 
values will do what you want. For example -c "-15:15" -w "-10:10"
 will make it red if it falls outside the range -15 ms to 15 ms, yellow if 
its outside the range -10 ms to 10 ms and green if it is in between -10ms and 
10 ms. The notations is standard nagios notation so you can do other fancy 
things with the ranges if you are familiar with that but the above should do 
the trick. 

Hope that helps,
Andy


On Apr 7, 2014, at 1:05 PM, Jianan Wang 
<>
 wrote:

> Hi Everyone,
> 
> I have a question about having Maddash display alarming red colour while 
> the latency value is minus. This maddash is operated on a LAN, so there 
> could be some minus latency issue from NTP synchronization precision. 
> Apparently the minus latency means the latency is under milisecond, which 
> should indicate the network is pretty good, so I just wonder if I could 
> tweak the Maddash to have latency values lower than zero display green 
> instead of red.
> 
> 
> Thanks.
> 
> -- 
> Jianan Wang
> Department of Electrical and Computer Engineering, Duke University
> Department of Optical Engineering, ZJU  Information Engineering
> Qizhen Leadership School, ZJU
> Tel:(1) 919-937-4582
> Email: 
> 
>