Can't stop the computer from sleeping or hibernating; lost SSH access

[Jeffrey Walton]

I'm using Ubuntu 20.04 LTS, x86_64, fully patched. I removed the stock window/desktop manager because Gnome3 and its derivatives suck. I installed Cinnamon desktop to get a usable desktop that I can interact with. The login manager is lightdm.

Despite my sincerest efforts, I cannot stop this computer from sleeping or hibernating. I've set my power management settings thusly:

* turn monitor off: 15 minutes
* turn disk off: never
* lock computer: off

I disabled apcid.service. I cannot find a setting in lightdm.conf to disable sleep or hibernation.

After about 15 minutes, the computer sleeps or hibernates and I lose my SSH connection.

The only workaround I have found is go over to the computer and login. Once logged in the computer honors the "no sleep" or "no hibernate" settings.

Ubuntu's wiki article on power management does not offer useful advice. I try things suggested in places like Ask Ubuntu and Super User but the problem persists.

Based on my searching this appears to be a widespread problem on Linux. Sadly, OS X and Windows don't seem to have these problems. Only Linux.

This is incredibly annoying.

[Fantu (fantonifabio)]

this seems related to systemd, try to check this for example:
https://askubuntu.com/questions/521620/prevent-machine-from-sleeping-when-ssh-connections-are-on