Morgaine wrote:Low cost is absolutely key when building clusters
Low cost per what though? the Pi has a low cost per unit but I don't think it has a low cost per anything else.
The real price of a a Pi from farnell/RS seems to be £30 (inc VAT) add in a SD card, power and network cables, port on a network switch, share of a power supply, slot in a case and it's probablly about £40 per Pi total
Meanwhile an i5 2500 costs about £160, add a motherboard, ram port on a network switch, case, etc and you will probablly be under £400 provided you don't waste money on an overly fancy motherboard or case.
In other words afaict a cheap i5 box costs less than 10 times as much as a Pi and is way more than 10 times "better".
I firmly belive that the ONLY reasonable use of a Pi cluster is to learn about clustering. For pretty much anything else you'd be better off with a smaller number of more powerful machines.