This is my slightly mad plan to build a 32 core, 64 GB virtualization cluster for as little money as possible.
I bought the first “layer” of this infinitely expandable cluster design to check that all the parts work together (in fact they don’t — see below).
The total cost was £304 (includes sales tax and delivery). The cost per core + 2 GB RAM is a very reasonable £38.
I’m planning to run the cluster caseless (or at least, I’m first going to examine the heat and EM-radiation by running this first layer caseless to see if it is feasible). And diskless, using PXE or a cheap USB key to boot, with the OS and guests located on a fast NFS server.
To stack up caseless motherboards in the final cluster, I’m using these aluminium stand-offs. Each stand-off is 1″ high. [Edit: See comments for a cheaper alternative]
Unfortunately even with 3 inches of stand-offs, the clearance over the processor fan wouldn’t be very much. If I go for 4 spacers (4″) then the total height of the final four board cluster would be more than a foot!
The second problem is that I’d forgotten that being AMD
there is no integrated graphics [not quite true, see comments]. These boards appear not to boot without a graphics card. The card will be completely useless in normal operation, just taking up space and power and adding to the price per core.
Another issue is whether I should just purchase one PSU per motherboard, or invest in Y-splitters such as this one. It’s not clear to me that a Y-splitter can power the CPU.
Thanks to Karanbir Singh for suggesting these processors. They are very cheap per core.