I'm having a small problem with one of my machines. When I reboot after the upgrade to 13.10, I end up at the initramfs prompt. If I do an
ls /dev/mapper
, I have nothing. If I wait a minute or two and do it again, it starts populating with drives. I can then type exit and the machine boots and works fine. Not quite certain how even to start debugging this problem.

In grub, my default linux kernel is:
linux    /vmlinuz-3.11.0-12-generic root=/dev/mapper/ubuntu--vg-root ro   quiet splash $vt_handoff
initrd    /initrd.img-3.11.0-12-generic