Whilst performing updates on Ubuntu server 16.04 we see the following warning. (Accepting it is a warning, it is none-the-less annoying).
Setting up initramfs-tools (0.122ubuntu8.3) ...
update-initramfs: deferring update (trigger activated)
Processing triggers for initramfs-tools (0.122ubuntu8.3) ...
update-initramfs: Generating /boot/initrd.img-4.4.0-38-generic
W: mdadm: /etc/mdadm/mdadm.conf defines no arrays.
The warning is displayed whenever there’s no ARRAY
line in mdadm.conf
The simplest fix for this warning is to add the following line to the end of /etc/mdadm/mdadm.conf
ARRAY <ignore> devices=/dev/sda