undefined | Better HN

0 pointsamluto2y ago0 comments

I think the Mac Mini has massively more compute than needed for this kind of work. It also has a power supply, and computer power supplies are generally not amazing at low output.

I’m imagining something quite specialized. Use a low frequency CPU with either vector units or even DMA engines optimized for the specific workloads needed, or go all out and arrange for data to be DMAed directly between the disk and the NIC.

0 comments

yencabulator2y ago

> or go all out and arrange for data to be DMAed directly between the disk and the NIC.

Ceph OSDs do a lot more work than you're imagining.

Palomides2y ago

sounds like a DPU (mellanox bluefield for example), they're entire ARM systems with a high speed NIC all on a PCIe card, I think the bluefield ones can even directly interface over the bus to nvme drives without the host system involved

amlutoOP2y ago

That Bluefield hardware looks neat, although it also sounds like a real project to program it :).

I can imagine two credible configurations for high efficiency:

1. A motherboard with a truly minimal CPU for bootstrapping but a bit beefy PCIe root complex. 32 lanes to the DPU and a bunch of lanes for NVMe. The CPU doesn’t touch the data at all. I wonder if anyone makes a motherboard optimized like this — a 64-lane mobo with a Xeon in it would be quite wasteful but fine for prototyping I suppose.

2. Wire up the NVMe ports directly to the Bluefield DPU, letting the DPU be the root complex. At least 28 of the lanes are presumably usable for this or maybe even all 32. It’s not entirely clear to me that the Bluefield DPU can operate without a host computer, though.

j / k navigate · click thread line to collapse