I'm fairly sure this is a known bug which is fixed in 3.1.3 which has just been released in Debian (I think).
The problem is that mdadm tries to use /lib/init/rw which doesn't exist during the initramfs stage. If you repeat your experiment with init=/bin/sh, and mkdir -p /lib/init/rw before starting udev, I think you will find that it works better. If you could either confirm that, or confirm that 3.1.3 works, that would be great. 3.1.3 uses /dev/.mdadm rather than /lib/init/rw. NeilBrown -- To UNSUBSCRIBE, email to debian-bugs-rc-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
