I've got a remote appliance, and its disk IO seems to have locked up, trying to run anything that isn't already loaded results in errors like this:

$ sudo shutdown -r 0
sudo: Can't open /var/lib/sudo/<machine_name>/0: Read-only file system
sudo: unable to execute /sbin/shutdown: Input/output error

I have SSH access to the appliance. I'm hoping that restarting the box will fix this (if not I have to go replace the box), but trying to restart it yields the above output.

Anyone have any ideas???