Problem :
Is there any union-type filesystem that can handle online edits to lower branches?
Use-case: OS configuration management
I wish to store my main OS in lowest dir. This dir should be the unconfigured OS. Let’s call the dir OSdir. Furthermore I need a place to store etc changes, so above OSdir I’d put a confdir. Lastly workdir above all of them. I’d like to be able to merge some changes from workdir to confdir. I do not want to reboot and boot into another system, just so I can edit some files.
With this setup, I could:
- See exactly which files have changed from the unconfigured system state
- Rapidly recover from a fatal system failure (assuming backup of
confdirsurvived)
I know that OverlayFS does not support this, because it is explicitly mentioned in the docs, however I failed to find info on the others.
Nevertheless: Is there any union-type filesystem that can handle online edits to lower branches?
Solution :
It does! It’s called “UDBA” (Users Direct Branch Access) and is described over here: