[Mageia-dev] Proposal: Updating released versions (long post)

[Buchan Milne]

On Saturday, 9 October 2010 10:10:36 Renaud MICHEL wrote:
> On samedi 09 octobre 2010 at 05:45, andré wrote :
> > Note that configuration files that have been changed from the
> > installation default are often already saved.  (Generally ".old" is
> > appended to the configuration file name, sometimes ".new" to the new
> > configuration file.)
> 
> But here you are only talking about system-wide configuration files, which
> are known of rpm as they are part of the package and marked as config
> files. But what about user specific configuration files?
> For the easy kind, where a program will have a single configuration file
> (or dedicated directory), a pre-inst script could find it in the home of
> each users and backup them. But you have cases of programs which have
> configuration scattered in multiple shared directories (like KDE), or even
> non-deterministic configuration files and it can become very tricky to find
> all the files to backup.

A snapshot-based solution (e.g. on btrfs) would mean you don't have to "find 
all the files".

> And you have the really hard kind, where the same configuration file may be
> shared by different packages. For example, plasma applet configurations are
> stored in a few ~/.kde4/share/config/plasma* files.

Well, now the problem is to snapshot multiple filesystems. I am not sure if 
this is easy with btrfs and subvolumes.

But, IMHO, the software in question should ideally be able to handle upgrade 
*and* downgrade, otherwise environments with shared home directories would 
have to be *very* careful about keeping *all* software on *all* machines 
exactly in step.

Regards,
Buchan