Fedora Rawhide Users Can Now Test The Experimental Zchunk Metadata Support

Zchunk is the file format announced earlier this year for delivering good compression while being delta-friendly and based upon Zsync and Casync while compression handling is done by Zstandard.

There was a plan to switch to Zchunk for repository metadata with Fedora 29, but that didn't pan out in time. Now the plan is to make the repo metadata switch for Fedora 30 and now it can be tested with Fedora Rawhide.

Fedora contributor Jon Dieter who has led the charge on Zchunk has now made available updated DNF and repo libraries through Copr that support Zchunk. Most importantly, Zchunk metadata generation is now enabled for Rawhide. The necessary package updates will land in Fedora Rawhide once there's been some testing done, but should you want to give it a try over the holidays, the Copr repository is ready for Rawhide users.

The goal is for the Zchunk metadata to speed things up for Fedora users with their DNF commands thanks to the package information having Zstandard compression and for being more delta-friendly in only needing to download what has changed. But initially only part of that holds true. Dieter commented that the current metadata isn't being compressed with the Fedora repodata zdicts, which is leading to the size of the files being roughly double that of the Gzip versions.

So there's still work ahead but those wishing to learn more or try out the experimental packages can find out the latest details on Dieter's blog.