On Wed, 10 Apr 2019 08:38:04 -0700, Benjamin Smith <lists at benjamindsmith.com> wrote >I drove to the site, picked up the machine, and last night found that the >problem wasn't anything to do with mdadm, but rather setting a partition to >GPT. For some reason, you *cannot* have a partition of type GPT and expect >Linux to boot. (WT F/H?!?) If you want to boot a BIOS based machine with a GPT boot disk you need to have a BIOS boot partition. Otherwise GRUB will have no place to write the necessary bootloader code. https://en.wikipedia.org/wiki/BIOS_boot_partition I found this out a few years ago when I replaced the 2 TiB MBR boot drives on my Fedora System with 3 TiB GPT disks (mdraid 1) <(*) Jyrki