On Wed, May 29, 2019 at 4:07 PM Neal Gompa <ngompa13(a)gmail.com> wrote:
This is news to me, as I've never heard of any "side mass rebuilds".
They're prohibitively expensive to do, which is why we do only one per
release anyway.
Is it sane to test this in Rawhide now with just new builds? As things
get rebuilt in rawhide, we should start seeing reduced times in
various installation tests, including the ones openqa does, I think
dozens of times every day.
I'm pretty sure this would break DeltaRPMs, since none of the
drpm
software has been updated to handle zstd compression. Neither drpm nor
deltarpm handle it today.
'dnf info deltarpm' says
URL :
http://gitorious.org/deltarpm/deltarpm
which has an expired certificate, but pushing passed that it says
current version 3.6 is 5 years old. Is this really maintained or
updatabled?
I see compression options in makedeltarpm, and zstd isn't in it. I'm
guessing we'd end up at line 580:
fprintf(stderr, "unknown compression type: %s\n", comp);
https://github.com/rpm-software-management/deltarpm/blob/3.6.1/makedeltar...
Anyway, I think optimizing for this is something rpm-ostree is better
suited for anyway. Due to the significantly faster decompress time of
zstd, whatever advantage there is of deltarpm is rapidly diminished.
Possibly the only way to know this is for someone to update deltarpm
to handle zstd and then test if the savings is still significant
compared to local reprocessing time.
> If we did this, wouldn't it make it very difficult to use
tools like
> mock on RHEL / CentOS 7 to build for Fedora 3x? Or does RHEL 7 RPM
> support zstd?
>
We're pretty much screwed here. Also, since RHEL 8's rpm package does
not have zstd support compiled in, it too cannot handle the RPMs.
Hence it needs to be configurable. Fedora EPEL RPMs need to be built
with xz. Everything else that's expected to be consumed by Fedora 29
and higher, can use either zstd or xz. I'd expect RHEL built packages
intended for Fedora would use xz, and Fedora's RPM would support that
just fine.
--
Chris Murphy