I have Khadas VIM board with Ubuntu Server Bionic 4.9 arm64 installed.
I want to turn on RAID1 to mirror two drives, but apparently this module is missing:
modprobe: FATAL: Module md_mod not found in directory /lib/modules/4.9.40
mdadm: Fail create md0 when using /sys/module/md_mod/parameters/new_array
mdadm: unexpected failure opening /dev/md0