I like to to "apt get update" on critical servers manually, watching the update scroll, looking for errors or weirdness. Then, the reboot. Gotta walk away for a couple of minutes, maybe make a post like this, to distract myself from the "will it boot" anxiety. Anxiety justified. Didn't boot. /dev/sda not found. F. Don't panic. Shut it down. Wait a minute and power it back up. Grab your towel and don't panic. Reboot. There it is! And all is good. Relax.