Mine is in the picture: 1544 days and counting!
It’s an EC2 nano instance that’s used only as a monitor for a few services that are running inside my VPN. It has served me well over all these years!
EDIT: before everyone starts screaming about “security”:
It’s not internet facing and no port is opened, all it does is fire up a notification if/when something doesn’t reply.
Even in the unlikely scenario that someone gain access to it that means that my VPN is already compromised, and I’ve got bigger problems to worry about.
I think I got up to 300 or so days on my old Athlon XP Gentoo server. I have “upgraded” since then and my current server can’t go more than 2 days. I have an arduino connected to the motherboards reset button pin that resets it whenever the bash script that communicates with the arduino stops running but even that somehow still crashes at least once a week and needs manual intervention.