perfSONAR User Q&A and Other Discussion

[Andrew Lake <>]

Hi Mike,

Also, the larger question you should consider is what are you hoping to derive from a latency dashboard with a bunch of owamp nodes this close together. As mentioned it’s a well-known fact (and been a matter of hot debate lately) that OWAMP measurements, due to their reliance on NTP, give unreliable latency results for nodes in close proximity. As such such, alerting on latency isn’t probably going to tell you much for these nodes. Alerting on loss as reported by OWAMP may have some uses, but the latency values probably won’t in this case.

Thanks,

Andy

On March 31, 2016 at 6:53:08 AM, Rade Martinović () wrote:

Hi Mike,

 

After looking into Nagios check that are used by MaDDash, I may have a suggestion,

 

Could compare switch and parameter compare_mindelay=s help you with this?

 

How your /etc/maddash/maddash-server/maddash.yaml looks like?

 

Thanks,

-- Rade

 

From: [mailto:] On Behalf Of Rade Martinovic
Sent: 31. March 2016 11:26
To:
Cc:
Subject: RE: [perfsonar-user] Negative Latency Times on MaDDash

 

Hi Mike,

 

I cannot give you any advice on this issue, but I am still curious,

 

Would you like negative values to be colored green – or perhaps some other color? Having negative latency is maybe a situation you would like to be aware of.

 

Can you share the URL to your MaDDash?

 

Best,

Rade

 

From: [] On Behalf Of Michael Reece
Sent: 30. March 2016 22:22
To: <>
Subject: [perfsonar-user] Negative Latency Times on MaDDash

 

I know that this issue has been raised before, but perhaps someone has a solution to it. For some reason the latency times between several of the nodes in my mesh are negative. I've been told before that this is likely due to the close proximity of the nodes in the mesh (most are less than a mile apart). This wouldn't really be a problem except for the fact these negative times show up red in the MaDDash latency grid. The legend states that only time of 10ms and greater will have the color red, but clearly the negative values are showing up red as well. Here is a screenshot of my latency grid on MaDDash:

Has anyone found a solution to this annoying problem? I would appreciate any help.

Thanks,

Mike Reece