#232 User directories as Btrfs subvolumes by default
Opened 2 years ago by ngompa. Modified 21 days ago

shadow-utils since version 4.7 has supported the ability to create user home directories as subvolumes.

As an iterative step toward supporting use-cases for isolating and protecting each user's data individually (to lay the groundwork for disaster recovery tooling as well as encryption as tracked in #82), it may be a good idea to start defaulting to creating subvolumes on creating new users when on Btrfs.

General Fedora Btrfs ticket is tracked as fedora-btrfs/project#50.

This seems like an aspect of the discussion about homed and user data encryption. Do we need a separate ticket for it?

This is orthogonal to homed, since we can do this without homed today.

This is orthogonal to homed, since we can do this without homed today.

But it seems like it would be better to wait and see how homed plays out? Or, if you think we should do it ASAP, then let's put that to the WG to decide.

The main value for doing it now is making it easier to something like Time Machine for user data, since snapshotting or doing btrfs send of a subvolume is possible.

Maybe some folks could try this layout locally, and see what happens? What are the cons? fedora-btrfs/project#50 has a couple of concerns listed: backup programs and the installer.

@lennart told us a few weeks ago that there's an early idea (perhaps it's "could happen" more than "will happen") of having systemd-homed learn about Btrfs snapshotting for this purpose; it already has subvolume support: A "btrfs" subvolume for each user, also located in /home/.homedir. This provides no encryption, but good quota support.*

Is the idea to have a way to convert from one subvolume regime to another? Just because it's subvolume based doesn't mean it'll "just work" with the systemd-homed way of doing things. Do we really want to do that work? We'd have to plan for that. Or alternative just wait and have one change instead of, in-effect, two changes? And while it's fairly simple to convert from one subvol regime to another (cp -r) it's harder to convert from one snapshot regime to another. We don't have a spec for any of that, it's all very tool specific with a ton of assumptions made by each tool.

And so on...

Seems like this would benefit from a wider discussion - setting the meeting label.

Metadata Update from @aday:
- Issue tagged with: meeting

a year ago

From last week's meeting:

ACTION: Neal to file the bugs he found and get them fixed. Then we can revisit this. Chris to help out too (cmurf, 03:46:54)

Metadata Update from @ngompa:
- Issue untagged with: meeting
- Issue assigned to ngompa
- Issue tagged with: pending-action

a year ago

Refreshing my memory on this:

  • shadow-utils set the home subvolume to be owned by root instead of the new user, need to verify if this is still a problem. If it is, file a bug.

@ngompa looks like you have the action item here.

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Btrfs Status: Backlog
Installing Status: Backlog