[Rpm-ecosystem] Zchunk update

[Jonathan Dieter]

On Tue, 2018-04-17 at 17:39 +0200, Michal Novotny wrote:
> On Tue, Apr 17, 2018 at 4:20 PM, Jonathan Dieter <jdieter at gmail.com> wrote:
> > On Tue, 2018-04-17 at 09:08 +0200, Michal Novotny wrote:
> > > Hello Jonathan,
> > > 
> > > Once it is in createrepo_c, we could try employing it in Fedora COPR.
> > 
> > Ok, done.  This copr currently has zchunk and createrepo_c in it.  I
> > did have to disable the python tests for createrepo_c which means I
> > probably wouldn't use the python bindings with this release.
> > 
> > https://copr.fedorainfracloud.org/coprs/jdieter/zchunk/
> > 
> > To enable zchunk creation, run createrepo_c --zck.  I've created
> > dictionaries that are appropriate for Fedora's metadata at
> > https://www.jdieter.net/downloads/zchunk-dicts, and they can be used
> > with --zck-primary-dict, --zck-filelists-dict and --zck-other-dict.
> > 
> > To make zchunk downloads efficient, the same dictionary must be used
> > each time metadata is generated.  Dictionaries aren't mandatory, but
> > they greatly reduce the size of the compressed metadata.
> 
> Alright, I will deploy it on staging. But we will need to get it into Fedora's 
> DistGit first to be able to use it on COPR production instance afterwards...
> Anyway, looking forward to start experimenting with it.
> 
> Thank you!

I'm assuming that you're referring here to getting zchunk packaged into
Fedora.  I'd really like to finalize the file format (we're close, but
I still need a good way of storing signatures in it) and the download
API before releasing it into Fedora proper.

I would recommend using the dicts mentioned above as they give me over
40% space savings for both other.xml.zck and primary.xml.zck.  Do
please let me know if you run into any problems.

Thanks,
Jonathan