[Beowulf] Anyone have experience with Cisco 6509 switches for a cluster?

[Michael Di Domenico]

Can we get a list of the Modules in the Switch?

I'd be willing to bet they don't have an MSFC card, and are just using
the SUP module

On Wed, Jun 15, 2011 at 10:27 AM, Joe Landman
<landman at scalableinformatics.com> wrote:
> Hi folks
>
>   A partner is rebuilding a beowulf rendering/post-production cluster,
> and they swapped out some smaller switches for a larger Cisco 6509
> switch frame.  They are encountering some issues, asked us for help.
> Unfortunately, I know very little about these switches and IOS (not the
> Apple bit), so I am hoping to get a pointer to what we should be looking
> for.  If anyone is an IOS/Cisco expert that can help today, please
> contact me offlist.
>
>   Here's the problem:
>
>   iperf between 2 nodes, wire speed.  117 MB/s.
>
>   iperf between 4 nodes, 1/2 wire speed, or 55 MB/s.
>
>   As they increase the number of pairs doing iperf, performance keeps
> dropping.
>
>   This suggests that all traffic is being serialized somehow, possibly
> transiting a single interface.
>
>   Anyone out there ever see something like this before?  Any clues as
> to how to handle it?  Or how to diagnose/fix this?
>
>   Thanks in advance.
>
> Joe
> --
> Joseph Landman, Ph.D
> Founder and CEO
> Scalable Informatics Inc.
> email: landman at scalableinformatics.com
> web  : http://scalableinformatics.com
>        http://scalableinformatics.com/sicluster
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