Hey friend,
I want to be very straight forward here in the hope that it’ll give you an additional perspective:
The scenario you’re describing I’d describe as “make the life of my surrounding as easy as possible when I bite the bullet”.
. That does not include making my system or even the home server easy to use or maintain. My interests don’t matter in that case only what those people need and would want. In my case: my non tech savvy wife would want to get rid of a big desktop PC but would most likely struggle because I enjoyed using it.
This means:
- For all data there are encrypted files with passwords and/or instructions.
- For all things no one would want there is a “this is how you get rid of it most easily” guide, including "call an electrician for the following recabling to pull out the shellies.
- for the one thing not easily ripped out there is a maintenance guide and a replacement guide (a bus system monster" temporarily" installed due to good reasons).
To be clear: no non tech savvy person I know would want to use my (and I guess your) custom systems. Not one. They’d rather have a “this is the ebay description” or a “this is how you install windows”.
Your legacy will find other ways to life on - it won’t be your tools and toys though.
Edit: I missed some complexity as suspected! I’m not sure how this process would handle hard and symlinks. Would add an experiment for that before going with the nix and root folders (it shouldn’t harm log at all).
Original text: Perhaps I’m missing some complexity in your setup but from my understanding it’s really straight forward:
The main caveat is that you need twice the space of your largest future sub volume. A garbage collect - d and any manual cleanup can help you there. I’d gets that approach with /var/log and when that works move over to the more critical systems.
If everything is working as expected, write a run book for every step and repeat with /home (i.e. have every step written up). Home is the second least critical folder for this.
Once you have your runbook repeat the process and when you run out of space resize as needed. (e.g. https://btrfs.readthedocs.io/en/latest/btrfs-filesystem.html#man-filesystem-resize)
That said: as you aim for the fully ephemeral root I personally would actually go the reibstwllwtion/reinstall route and write up everything I needed to do by hand. But that needs even more spare space (I’d prefer even a second disk for stuff like that to have a fallback).
Good luck!