Demi Marie Obenour <demiobenour@gmail.com> writes:

> What size should the A and B partitions be?  I can’t think of
> any reasonable way to size them that is also future-proof.

I think we need to just do our best estimate, erring on the side of them
being larger, and I don't think we'll even be in a position to estimate
that until we've done work on minimizing dependencies etc., but
obviously we will need to come up with an answer to this before we start
encouraging people to install an image.

If we pick too big, will we be able to shrink them later for new
installs?  Will it be possible for space-constrained users to manually
partition with smaller sizes?

> Android had the same problem, and they solved it by using
> device mapper.  Unfortunately, I doubt LVM meets our security
> goals, which means a whole new userspace implementation would
> be required.  That would not be fun, especially since a bug
> would require a reinstall to correct.
>
> Other image-based Linux distros generally don't have this
> problem because they use filesystem or ostree snapshots,
> rather than separate partitions.  Chromium OS has a whole
> team of paid developers, so I think they can deal with
> constraints a bit better than we can :).
>
> One horrifying worst-case option is to add a file on the
> user data partition, create a loop device based on it,
> and then add it to the dm-verity table.  I really don't
> want to do that if there is any other option, though.
> -- 
> Sincerely,
> Demi Marie Obenour (she/her/hers)