Annoyingly, disk discovery. It refused to use my disks, claiming they didn’t have serial numbers. I could see the serial numbers in the fronted and the console, but their middleware just hated them.

I am using a USB multi-disk drive thing, which didn’t work properly on an old kernel, but it should have been fine with the new kernel.

I reported the bug, which didn’t really get addressed, and then had to build my array using the command line tools (which aren’t documented).