Always remember that
as the uptime grows, the chance of not being able to restart susccessfully increases.
That is, unless you take some special precautions.
Had an UPS fail on our QNAP, like a couple of days ago. Before that, the uptime was something like several months. Lo and behold, the QNAP failed to come back online. It just sit there "SYSTEM BOOTING >>>" with all the drive LEDs blinking, no ping, nothing, and looked very much like a power supply failure. However, all the LEDs were blinking, and generally it look very busy doing something for about 30 hours I let it sit. When I finally get around to connect a VGA to it, there was nothing to be seen.
Then, a couple of hard reboots took care of the problem, at least for the time being.
Looks like next time the PSU has to be replaced.