perfSONAR User Q&A and Other Discussion

[Raul Lopes <>]

Hi Andy,

 

The hosts are all perfSONAR 5.0.5.

 

DNS is resolving in less than 0.02s.

 

And iperf3 is the same: 3.14-1.el7 from @perfSONAR.

 

And ntp seems fine.

 

Regards,

Raul

 

From: Andrew Lake <>
Date: Thursday, 5 October 2023 at 20:06
To: <>, Raul Lopes <>
Subject: Re: [perfsonar-user] Iperf3 error

Hi Raul,

 

I’ve run into errors like that when there are timing issues between the hosts and pscheduler is slow to start the server or the client starts after the server gets brought down. There is multiple seconds of buffer built-in to pscheduler so it has to be something that slows things down by multiple seconds. A few things to check:

 

1. Are all the endpoints running 5.0.4 or later? It has a fix that removes some logic that was causing things to logjam if DNS was taking awhile.

2. Related to #1, is DNS configured properly? are DNS queries returning in < 1s? You can try the pscheduler tests with just IPs. If they work, may be some DNS issues slowing things down.

3. Not timing related: any strange versions of iperf3 running on those hosts? I’ve ran into cases before where the older version of iperf3 in the main Ubuntu repos gets pulled down and causes issues. 

 

Could be something else as well, but above are a few things I’ve ran into before.

 

Thanks,

Andy

 

 

On October 5, 2023 at 2:13:15 PM, Raul Lopes () wrote:

Dear experts,

 

In what conditions would you expect to see the error

 

   Unable to parse iperf3 output as JSON: Expecting value: line 1 column 1 (char 0)

 

This in a pscheduler throughput test for two hosts A and B that pass troubleshoot  and that run pscheduler tests with another 20 hosts.

 

Also, iperf3 from the command line works perfectly from A to B and B to A.

 

Regards,

Raul

 

 

 

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