aufs based upgrade tests

[Lars Wirzenius]

to, 2009-03-19 kello 16:20 +0100, Martin Soto kirjoitti:
> Seconded, you start your session once with the new version installed,
> and there's often no way back. Applications will surely update their
> configuration data as soon as they're started, and there's no guarantee
> that they'll work when the older system is reinstated.

In my humble opinion, such applications are broken. They will already
break when, for example, $HOME is shared over NFS, and different hosts
are not completely in sync, version-wise.

> As a possible solution, what about putting user accounts under aufs as
> well? This would have the advantage of allowing for testing how
> applications update their configuration data, which is also a good idea
> because this is a common source of bugs.

This seems like a good idea, so I second it, because applications often
are broken. It might be good to optionally allow /home to be excluded.