[Beowulf] if you had 2 switches and a bunch of cable,what would you do?

[Hearns, John]

Option 1. Create 2 separate internal networks. In wiring drawings for
clusters, I often see one administrative network and one for
computations (mpi, and so forth).


Paul, definitely recommend option 1.
Use the second switch for MPI traffic.

The way you achieve this is to use your batch scheduling system and run
a script
which takes the machines list provided by the batch system and
translates it into one
which is fed to to the mpirun utility, ie the hostnames are turned into
something like 
hostname-eth1


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