[Beowulf] test network link quality?

[Andrew Howard]

iperf can also be a nice way to diagnose problems. In our 10gig
networks, we've noticed that occasionally cables of dubious quality
pop up and cause issues with packet flow in either one or both
directions. Using iperf we can see nodes that don't perform properly,
and we notice a lot of problems that don't show up with simple ping
tests.

-- 
Andrew Howard
ahoward at purdue.edu
Assistant Research Programmer
Rosen Center for Advanced Computing, Purdue University

On Fri, Apr 2, 2010 at 12:15 PM, David Mathog <mathog at caltech.edu> wrote:
> Is there a common method for testing the quality of a network link
> between two networked machines?  This is for situations where the link
> works 99.99% of the time, but should work 99.99999% of the time, with
> the failures being dropped packets or whatever.  This would be used for
> tracking down slightly defective patch cables, switch ports, NICs, and
> the like.  Is ping used like this:
>
>  ping -i .0001 -c 1000000 -f targetmachine
>
> adequate?  It gives decent statistics, but doesn't seem like a very good
> simulation of a typical network load, in particular, the packet contents
> aren't varying.
>
> Thanks,
>
> David Mathog
> mathog at caltech.edu
> Manager, Sequence Analysis Facility, Biology Division, Caltech
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