= Proposed System Wide Change: Zchunk Metadata =
https://fedoraproject.org/wiki/Changes/Zchunk_Metadata


Owner(s):
  * Jonathan Dieter <jdieter at gmail dot com>
  * Neal Gompa <ngompa13 at gmail dot com>


All dnf repository metadata will be compressed with the zchunk format rather than xz or gzip.


== Detailed description ==
Currently Fedora's repository metadata is compressed using the xz and gzip formats.  Zchunk is a new compression format designed to allow for highly efficient deltas.  When Fedora's metadata is compressed using zchunk, dnf will download only the differences between any earlier copies of the metadata and the current version.


== Scope ==
* Proposal owners:
** Package zchunk for Fedora
** Get the pull requests to enable zchunk in dnf, libdnf, librepo, libsolv and createrepo_c merged upstream
*** https://github.com/rpm-software-management/librepo/pull/127
*** https://github.com/openSUSE/libsolv/pull/270
*** https://github.com/rpm-software-management/dnf/pull/1107
*** https://github.com/rpm-software-management/libdnf/pull/478
*** https://github.com/rpm-software-management/createrepo_c/pull/92
** Create a new package for Fedora's zchunk dictionaries.

* Other developers:
Fedora Infrastructure needs to start creating zchunked metadata

* Release engineering:
#7600 [https://pagure.io/releng/issue/7600]

** List of deliverables:
Zchunk repository metadata

* Policies and guidelines:
Packaging guidelines are not affected by this change.

* Trademark approval:
N/A (not needed for this Change)