dracut: qestions about mdraid module

[Francis Moreau <francis.moro-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

Hello,

I'm looking at the module 'mdraid' of dracut (0.38) and was wondering
the purpose of rd.md.uuid= parameter.

I understand it can be used to selectively activate the array matching
the UUID passed through the parameter but I'm wondering in which cases
it can be useful...

Also I don't really understand why dracut try to do its own mechanism to
achieve that (by providing its own udev rules which are modified at boot
time) whereas mdadm already provide the infrastructure (through
mdadm.conf) in a cleaner way (IMHO).

Another question, hopefully you don't mind: dracut provide an udev set
of rules in a file named 59-persistent-storage-md.rules. I still don't
really see the point since most of the stuff in it seems to already be
done by the rule fileudev-md-raid-arrays.rules, shipped by mdadm (3.3.2).

Ah my last question not related to mdraid: why dracut uses stderr to
print out all its messages: info, debug, error. Stderr is usually used
for error/warning messages only.

Thanks !