[aur-general] mkinitcpio/mdadm/mdadm_udev fail to start raid10

[Ido Rosen]

The the default configuration under ArchLinux and DEVICE partitions in
mdadm.conf, mdadm and the mdadm mkinitcpio hook fail to load the
raid10 kernel module automatically, and as a result raid10 arrays fail
to load on boot in Arch.

My temporary workaround is to include the raid10 kernel module in the
mkinitcpio.conf MODULES= list, it could also be included in
/etc/modules-load.d/*.conf, but this should not be necessary, and is
currently not necessary for raid1 arrays.  I do not think this is an
upstream problem since my LFS and Gentoo boxes do load the correct
(raid10) kernel module without any specific configuration to do so.

Has anyone else replicated this behavior?

Suggestions:

- Preferred: Make the initcpio hook/mdadm udev rules/whatever loads
raid1.ko normally also detect raid10 (and raid5, raid6, ...) arrays
properly.

- Alternatively: Add a section to the SW RAID wiki page describing how
to make the module load persist on boot
(https://wiki.archlinux.org/index.php/Software_RAID_and_LVM#Load_kernel_modules)

Ido