Fedora 29 To Change DNF's Repository Metadata Compression To Zchunk

[phoronix]

Phoronix: Fedora 29 To Change DNF's Repository Metadata Compression To Zchunk

Fedora 29 continues looking like a rather ambitious release with a growing number of changes, including at some of the lowest levels of the system. The latest feature proposal is on changing the compression scheme used by the DNF package manager's repository metadata...

http://www.phoronix.com/scan.php?page=news_item&px=Fedora-29-Metadata-Zchunk

[andrebrait]

Anything that helps not having to download 35MB of data just to check if there are updates is an improvement

[Weasel]

Zchunk doesn't offer "better compression" than xz/LZMA2 as the article implies, it's not even close. Maybe better than gzip...

[nanonyme]

Zchunk doesn't offer "better compression" than xz/LZMA2 as the article implies, it's not even close. Maybe better than gzip...

Improved diffability may make less efficient compression a negligible thing though

[Weasel]

Yes, the transfer times will be lower, I didn't say it's a bad change.

But claiming Zchunk offers better compression is just misleading for any other use case (these are general purpose algorithms). Even zstd is worse than xz in terms of compression ratio, and zchunk is worse than zstd since it adds diffability (it uses zstd at its core) which splits it into chunks.

Note by "worse" I'm talking strictly about compression ratio. In this case it's obviously a good thing to have diffability, but not for compression ratio (other cases).

[fuzz]

Hmmm, I wonder what performance would be like if Gentoo adopted this as an option for Portage.