[gentoo-user] Run command after root mounted ro?

[Daniel Frey <djqfrey@gmail.com>]

Greetings,

I discovered a possible reason for mdadm always marking my raid array as
bad on reboot. The problem is I don't know how to check for the issue.

When using root on a native mdadm raid, the kernel handles the array
state transition at shutdown, so it's not a big deal. However, it's
different when using external metadata - mdadm must be called before the
reboot.

Apparently mdadm must be called after the root filesystem is mounted
read-only. Then it can mark the array as clean and not rebuild every
single reboot.

Where do I check this? The /etc/init.d/mdadm script happens well before
root is mounted read-only.

Apparently `mdadm --wait-clean --scan` needs to be called so the
external metadata is updated correctly. If you use this command with a
native mdadm raid it does nothing, but it's critical apparently to the
health of other metadata types.

I've grepped through /etc/init.d/ and found nothing.

Dan