[Beowulf] building a new cluster

[Joel Jaeggli]

On Wed, 1 Sep 2004, Robin Laing wrote:

>> I'd look at the 2848, 21xx is unmanged. They don't (currently) support 
>> jumbo frames until the new firmware ships. the 41xx chassis will never 
>> support jumbo's and it's really any aging platform at this point, the 
>> switch fabric on the 28xx has more than 3x the capacity of the fabric in 
>> the 41xxx chassis.
>
> I wonder why you need a managed switch?
>
> Our cluster has one managed switch and one un-managed.  It isn't big but from 
> what I read before, management can slow down throughput.

Maybe if you have a layer 3-switch with some acls on it, but a managed an 
an unmanged l2 switch forward ethernet frames in exactly the same way.

Mostly maanged switches for small clusters are good because you can see 
when your ethernet interfaces autonegotiated properly, diagnose error 
conditions, do port trunking if you have nfs servers connected to it and 
so forth...

>  As I was limited to 
> one manufacturer (political) I chose the switch with the fastest throughput. 
> No managed switch was rated as fast as the unmanaged switch.

The biggest managed switch we have has a 720Gb/s crossbar, that's by no 
means the largest switch out there, I haven't recently seen any unmanged 
switch with more than 48 ports.

> Our local supplier has a 3 year warranty as well.  Rackmount cases and such. 
> We ended up with an extra machine due to savings from not dealing with a 
> major supplier.
>

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Joel Jaeggli  	       Unix Consulting 	       joelja at darkwing.uoregon.edu 
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