[Rpm-maint] Removing repackage and (auto)rollback?

[James Olin Oden]

On Feb 20, 2008 8:45 AM, James Antill <james.antill at redhat.com> wrote:
>
> On Wed, 2008-02-20 at 08:20 -0800, James Olin Oden wrote:
> > On Feb 19, 2008 8:54 AM, James Antill <james.antill at redhat.com> wrote:
> > >
> > > On Tue, 2008-02-19 at 11:15 -0500, seth vidal wrote:
> > >
> > > > Do you like the perform an lvm-snapshot in pre-trans and allow rolling
> > > > back in post-trans as reliable rollback method?
> > >
> > >  The problem is that while FS LVM snapshot+rollback might be reliable
> >
> > Please explain your reasoning.  I don't get why its untenable.
>
>  Because you can't guarantee that rpm is the only thing accessing the
> FS. Indeed some things, like logfiles, are pretty much guaranteed to be
> changing the FS. So unless you had complete FS transactions that you
> could rollback, and made sure all the things rpm did was within a
> transaction, rolling the entire FS back is worse than the problem IMO.
>
It is true that other things will be running that have open files that
are actively writing to them.   The thing to do is to bring down the
things that matter (e.g. databases, critical apps) and then take your
snapshots.  Somethings like logfiles don't really matter to a large
degree.  The whole point again is that if you really want to guarantee
a rollback, then you have to apply some level of discipline to your
upgrades.  Forcing package authors to write for rollbacks, though, is
a non-starter.

...james