I'm using Ubuntu 14.04 at Rackspace. What could cause the root fs to not appear here?
# df
Filesystem 1K-blocks Used Available Use% Mounted on
none 4 0 4 0% /sys/fs/cgroup
udev 2021824 12 2021812 1% /dev
tmpfs 409756 252 409504 1% /run
none 5120 0 5120 0% /run/lock
none 2048772 0 2048772 0% /run/shm
none 102400 0 102400 0% /run/user