I call this nonsense host ‘Ghost’, for me it’s similar to a tape backup solution. Fairly simple concept, it’s an old Pi1 + external mechanical drive that sits dormant with its ethernet off. Once a month, at a random time and random date it enables the ethernet, spins up the drive and pulls data from the main server to update its drive then goes black until next month. The only way to check or maintain the pi is a push button that toggles the ethernet interface. I slapped it together with some scrap wood, spare hardware and screwed it to a 2x4 in a dark corner of my basement. It’s my 5th string backup, the ultimate insurance policy because I’m mental.
That’s a cool idea for an automated offline backup. My equivalent is an external hard drive connected to a mechanical timer plug. Every day it turns on for 30 minutes, that triggers a script that mounts the drive, syncs my files, then unmounts the drive. Then the plug turns off the drive until tomorrow.
I like this better though. I’ve got an old pi1 somewhere, might have to try it.
This was my first idea but I got uneasy about an external device hard disconnecting. I was worried about data loss and corruption so I settled on just turning Ethernet on and off.