Or is this a bad idea?
Reading through !selfhosted, I think I have found a new hobby. I have an old laptop HP ProBook 450 G5 4WU81ES.
16gb ram, solid CPU, shitty integrated gpu, and only 256gb ssd. Barely enough for system and some apps. Battery life maybe 30min unplugged so I take it as an UPS.
So the question again is, can I have permanently plugged external hdd to use as extension for this purpose?
Yes you can: sudo pmset disablesleep 1
Ah, okay! I remember this being discussed when I saw this image posted for the first time, and that’s where I got that info from.