Some old stuff, some new stuff...

I received more stuff and here is the situation:

• Raspberry Pi:
  • 4× 3B+  (making one high performance quad)
  • 2× 3B
  • 2× 2B (together with the 3B, that makes another quad with slightly less performance)
  • 8× 1B+ (that's 2 quad with low performance)
• Hubs :
  • 4× 5 ports
  • 4× 8 ports
• RJ45: I have found 4× very short patch cables, I need more but don't want to order them. So I crimp them myself to measure, I received a bag of RJ45 plugs and I can finally use the old broken cables that were accumulated through all these years...
• SD cards : Found several from old project, and bought 12 during the sales. These should be enough for 3 quads: 6×8GB and 6×16GB. Usually I keep my images limited to 4GB, more is possible but I prefer when the storage is managed properly and centralised. Ideally the SD cards are mounted in read-only to prevent wear out.
• To ease SD card duplications, I ordered a few USB adapters. It seems that my internal port has gone kaputt anyway...
• Temperature management : I should by default stick a heat spreader on all the Pi's CPUs, just to keep the temperature reasonable and prevent the automatic clock throttling from kicking in. An extra undervolted 12V fan will increase airflow without being too noisy.

So far it seems I can shoot for a cluster of 4 quads, or 16 Pis, or 64 cores if I slowly replace the old single-core boards with newer ones. I hope that the overall throughput will help me with my current projects... The nice thing is that it is scalable and features can be added progressively. Another order of magnitude can then be gained once the GPU is harnessed. For now I need brute-force trivial jobs and it could evolve later, for example with distributed memory, so short and fast messages will become critical.