Ok, I found this also on older desktops with rotational disks (all the four ones mentioned have SSDs) running Ubuntu 12.04.1.
As Ted points out, it looks like Ubuntu (Upstart?) has issues with shutdown, but could there be a race exposed by the superb speed that Upstart is executing the umount/remount-ro, disk-cache-flush and kernel-reboot vector sequence?
Ok, I found this also on older desktops with rotational disks (all the four ones mentioned have SSDs) running Ubuntu 12.04.1.
As Ted points out, it looks like Ubuntu (Upstart?) has issues with shutdown, but could there be a race exposed by the superb speed that Upstart is executing the umount/remount-ro, disk-cache-flush and kernel-reboot vector sequence?