Using hardware RAID on Arch Linux

I recently installed Arch Linux on my Vaio Type Z and had some problems using the hardware RAID so here’s how I managed to make that work.

The installation process is of course perfectly normal. On my computer, after having enabled the hardware RAID, I had a /dev/md126 device and partitioned to have /dev/md126_1 mounted on /boot. After installing GRUB on the MBR with

grub-install /dev/md126

I tried to boot. GRUB launched properly, however, when trying to boot Arch Linux with the root supposed to be on /dev/md126_5, I had an error telling me that this device was not being found. After looking up in mkinitcpio’s documentation, I saw that there was a hook for FakeRAID so I booted from a Live USB, chrooted and add this hook with

pacman -S dmraid
vim /etc/mkinitcpio.conf # add dmraid to HOOKS
mkinitcpio -p linux

After rebooting, Arch Linux booted properly with the hardware RAID enabled.