Fedora 31 Considers Compressing Their RPM Packages With Zstd Rather Than XZ
Fedora has been using XZ-compressed RPMs for the past decade but with the Fedora 31 release due out later this year they are currently evaluating a switch over to Zstd compression.
The switch from XZ to Zstd compression for Fedora RPMs is currently being considered in the name of greater decompression performance. Tests done by Red Hat engineers show this would pay off big time in much faster decompression speeds -- around a third of the time it takes to decompress XZ'ed RPMs currently either to Tmpfs or an actual on-disk file-system. If going for the Zstd Level 19 compression level that's being considered, it would also offer a much better compression ratio. At present, Fedora's XZ-compressed RPMs are done at level two.
Moving to Zstd-compressed RPMs would mean faster installs/upgrades, faster container builds, lower bandwidth requirements of repository mirrors if going for a higher compression level, and similar benefits.
Switching to Zstd-compressed RPMs would break support for using these newer RPMs on those still relying upon Fedora 27 or older, but Fedora 28 and newer would be compatible with these newer RPMs. There's also the possibility of breakage for other RPM-based Linux distributions trying to leverage Fedora RPMs not compatible with Zstd-compressed payloads.
More details via this change proposal still to be evaluated by the Fedora Engineering and Steering Committee.