Backblaze, the online backup company, has posted a lengthy blog entry about the custom hardware they’ve designed to store customer data:
A Backblaze Storage Pod is a self-contained unit that puts storage online. It’s made up of a custom metal case with commodity hardware inside. Specifically, one pod contains one Intel Motherboard with four SATA cards plugged into it. The nine SATA cables run from the cards to nine port multiplier backplanes that each have five hard drives plugged directly into them (45 hard drives in total).
The design is impressive, but the fact the company is open about their design is even more impressive.