Answering Questions about the PetaPi

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2022-06-23 08:00:04

A few weeks ago, I posted a video about the Petabyte Pi Project—an experiment to see if a single Raspberry Pi Compute Module 4 could directly address sixty 20TB hard drives, totaling 1.2 Petabytes.

And in that video, it did, but with a caveat: RAID was unstable. For some reason, after writing 2 or 3 GB of data at a time, one of the HBAs I was using would flake out and reset itself, due to PCI Express bus errors.

Since publishing that video, I've done a lot more testing, based on suggestions from viewers and the Broadcom engineers I've worked with to get some of their LSI HBAs and RAID cards working on the Pi.

I also made a video for this blog post answering even more questions than I do in this blog post, like 'what does it sound like when 60 enterprise hard drives power down?'—check it out here: It works! 1.2 Petabytes on the Raspberry Pi.

The first thing I tried was upgrading the firmware on the HBAs—four Broadcom 9405W-16i cards. I noticed they were on version 5, which was from November 2017. A lot has changed in the past five years, and HBAs and RAID cards see a lot of active development to fix bugs, optimize throughput, etc., since they basically run their own on-chip OS.