[Beowulf] IB Cluster Configuration Options

[Michael Huntingdon]

We're working on a 64 node dual core Opteron cluster with a wide variety of 
mpi heavy applications and have run into the typical funding issues that 
are forcing some configuration restrictions (down sizing the wish list). 
The original concept included a 64 node, dual processor, dual core cluster 
with an Infiniband 9288 or 9096.

As a means to reduce our cost the suggestion was raised to cascade 4 9024 
switches, or reducing the node count, Opteron clock rate, and memory. Just 
wondering how severe the hop penalty might be in the case of cascading 
switches?

ciao~
michael