perfSONAR User Q&A and Other Discussion

[Brent Draney <>]

That is a lot to absorb.  Is it possible to create a picture of the network and which tests are slow vs normal?  I would check for crc errors on the slow path and hopefully something confesses.  It could be as simple as a failing optic on either the send or receive side.

Thanks,

Brent

On Nov 26, 2019, at 8:38 AM, Ian Gandon <> wrote:



Hi All,

 

Bit of a strange issue I’m experiencing and not even sure it sits in this realm but hoping you may have a suggestion.

 

We have a perfsonar test point installation on a device in our local office which has been functioning for a number of months. One of the tests is a bandwidth test which runs every 10 mins. The destination of the throughput test is a CentOS 7 server which exists in our network core at another site. This server also acts as a measurement archive for the node and is a virtual machine. All has been working normally then last Friday evening the bandwidth suddenly dropped to 1.0-1.3 Mbps expected is closer to 100Mb.

 

My first thought was an issue with our network so have done the leg work to investigate and can find nothing wrong. I’ve run several manual iperf3 tests as below:

 

Manual test from our local office to the MA – slow

Manual test from our local office to the MA – Reverse flag – Normal result

Manual test from our local office to a different server on the same VM host – Normal result

Manual test from a different host on a different subnet to the MA – slow

Manual test from a different host on a different subnet to a different server on the same host as the MA – Normal result

Manual test from MA to local office – normal result.

Perfsonar scheduled test from local office to the MA – slow.

 

I’ve been through the perfsonar logs on both the MA and test point but as the test isn’t failing there isn’t much to see. The results above seem to point to something on the MA itself throttling the results as everything outbound from the MA or to a different destination seems to work normally.

 

Any ideas?

 

Thanks for any assistance.

 

 

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Ian Gandon Network Infrastructure Systems Administrator Direct Dial: +44(0)20 3434 2146 Office: 0844 775 0000 Email:  www.onwave.com  <image002.png>   <image003.png>   <image004.png>

 

 

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