On Mon, May 25, 2009 at 1:16 PM, Christopher James Halse Rogers <r...@ubuntu.com> wrote: > On Mon, 2009-05-25 at 11:12 +0800, Christopher Chan wrote: >> That is not the case with OpenSolaris based ZFS root capable >> installations. While the whole disk maybe taken up by a zfs pool, the >> installation will create at least three zfs filesystems. ROOT/, >> ROOT/opt, export, and export/home all exist on my OpenSolaris >> installation. So all data is stored in the user's home directory and is not >> at all affected by upgrades or downgrades. >> > So, what happens when, say, I upgrade to a new version of Evolution and > it decides to convert all its existing mailboxes to the new database > format on first run, and I later want to revert because of new bugs? It > doesn't matter that I can roll back everything but /home to the previous > Evolution version - that mail is now essentially gone as far as the old > Evolution is concerned. > > Alternatively, replace Evolution with MySQL or such. > > This is what I understand to be the hard problem in *supporting* package > downgrades.
The first step would be to make it an unsupported option, like universe packages. After that, every package must be tested for downgrading. Just like the new notifications, it will suck a little until it gets better. A copy of the original settings in case of incompatible changes is a relatively simple solution. Downgrade conversion is probably not feasible for any but the most popular packages. Remco -- Ubuntu-devel-discuss mailing list Ubuntu-devel-discuss@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-devel-discuss
