On 9.7.2018 23:52, Josh Boyer wrote:
On Mon, Jul 2, 2018 at 1:19 AM Jan Kurik <jkurik(a)redhat.com>
> = Proposed System Wide Change: Zchunk Metadata =
> * 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
> == 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.
How does this work with distribution upgrades? If we only produce
zchunk compressed metadata, but dnf in f28 doesn't even understand it,
that seems wrong.
As I understood it form one fo the previous discussions about the topic,
zchunk will be only provided together with xz. Older dnf will simply
request xz and newer dnf will request zchunk but fallback to xz if it is
not available or checksums don't match or whatever error occurs.