Comment 19 for bug 103177

Same problem here:
The mdadm tries to assemble /dev/md0 before /dev/sda1 and /dev/sdb1 appears.

Workaround:
1) Boot kernel with break=mount (This causes the initramfs to pause somewhere before mdadm but after udev)
2) Wait a few seconds while udev detects /dev/sda1 and /dev/sdb1
3) Press Ctrl-D to continue startup, mdadm can now assemble /dev/md0

I suppose the "sleep 10" workaround in one of the initramfs files will solve my problem, but i was hoping for something cleaner to show up.