So, I'm confused. That slide says 64 cores, but the Parallella board website says 18. Which is it? You really need a proper benchmark.

Another question: how are you planning to implement fault tolerance? If you're running across hundreds of nodes via the internet, the probability of one failing while my job is running is high. Are you going to run a fault-tolerant scheduler?

And: how are you going to do file I/O? Does the user have to run the master MPI process on his/her own machine and do I/O there?