Michele Bini wrote:
[...] But then I tried to shutdown (via shutdown -r now) and I cannot.
I forgot to say that the failed disk (/dev/sda) is completely dead (probably on-board electronics problem, as accessing it gives i/o errors on each and every block and the hd light is stuck on).
Also, blindly guessing, I tried and removed the dead disk from the array: # mdadm /dev/md0 -r /dev/sda1 # mdadm /dev/md1 -r /dev/sda3 but nothing changed.