Comment 81 for bug 631795

This sounds similar to what I experience.

On every cold boot, dmraid fails to create devices nodes for a secondary software raid 1+0 device, which means that the "failed to mount, s to skip mounting or m for manual recovery" message is shown. I have to hit M, type dmraid -an, dmraid -ay and exit shell again to have the system boot normally. (just typing dmraid -ay doesn't work - I have to deactivate raid sets first.)