Hi, Ludovic Courtès <l...@gnu.org> skribis:
> https://web.fdn.fr/~lcourtes/software/guix/1.1.0rc2 > e830c2a8de vm: Transparently compress iso9660 images. Here’s a comparison of the size of the ISO images for rc1 and rc2: --8<---------------cut here---------------start------------->8--- $ du -h release-1.0.1.13450-01d5f2/guix-system-install-1.0.1.13450-01d5f2.x86_64-linux.iso.xz release-1.1.0rc2/guix-system-install-1.1.0rc2.x86_64-linux.iso.xz 260M release-1.0.1.13450-01d5f2/guix-system-install-1.0.1.13450-01d5f2.x86_64-linux.iso.xz 405M release-1.1.0rc2/guix-system-install-1.1.0rc2.x86_64-linux.iso.xz $ xz -d < release-1.0.1.13450-01d5f2/guix-system-install-1.0.1.13450-01d5f2.x86_64-linux.iso.xz | wc -c 1524205568 $ xz -d < release-1.1.0rc2/guix-system-install-1.1.0rc2.x86_64-linux.iso.xz | wc -c 589223936 --8<---------------cut here---------------end--------------->8--- As you can see: • The xz-compressed ISO of rc2 is 1.6 times bigger than that of rc1. • The uncompressed ISO of rc2 is 2.6 times smaller than that of rc1. It’s not surprising that xz has a hard time compressing an already-compressed image, but I find it surprising that the end result is almost twice as big. “make release” uses the default xz compression ratio, -6. I tried different levels and different compression tools (though I don’t want to change from xz now because this would likely break documentation and links all around) and it seems we can’t really do any better: --8<---------------cut here---------------start------------->8--- 560M /tmp/t.iso 415M /tmp/t.iso.gz 406M /tmp/t.iso.lz-6 412M /tmp/t.iso.xz-0 407M /tmp/t.iso.xz-3 404M /tmp/t.iso.xz-8 --8<---------------cut here---------------end--------------->8--- Thoughts? Ideas? Ludo’.
