[Rpm-maint] RFC: Relocate RPM and DNF databases to /usr

[Colin Walters]

On Mon, Jan 3, 2022, at 2:44 AM, Panu Matilainen wrote:
> On 12/16/21 16:41, Colin Walters wrote:
>
>> I didn't wake up one day and say "hey you know what, today I'm going to move the rpm database just for fun".  Neither, for that matter did the OpenSUSE folks.  We haven't had this conversation over and over throughout the years just because it was some minor thing.
>> 
>> What I *did* wake up one day and say I'm going to do is make upgrades transactional and offline by default and hence safe.  No one should ever fear starting an operating system upgrade while their laptop is at 30% battery.  Administrators running important servers must be able to easily roll back when the kernel *or* systemd (or something) else regresses, because it's software, it regresses all the time despite our best efforts.
>> 
>> So yes again, this does matter.  And it matters because whether you're doing "image based upgrades" like ostree or just "client side offline updates" like the https://kubic.opensuse.org/documentation/man-pages/transactional-update.8.html thing - it's very important *what data specifically* is versioned/snapshotted and what isn't.  On an ostree system for example, it's completely normal that there are *two* rpm databases (one you're running, one that's pending in the new root).
>> 
>> All the data in the rpmdb is about content that's in `/usr`.
>
> But that's just plain, utter bollocks.
>
> On modern distros, MOST of rpmdb may be about /usr content but most is 
> not all, not by a long shot. If that's an assumption this change is 
> based on then it needs to stop right there.

There is indeed the `/opt` issue that Florian raised.

But is there other data you're thinking of?