1303190 - Use xz for linux 'installer' format

Status: NEW

(Release Engineering :: General, task)

Description

[Chris AtLee [:catlee]]

Switching to xz instead of bz2 would save quite a bit on the final installer size for Firefox on Linux.

52884219 firefox-46.0.1.tar.bz2
46248136 firefox-46.0.1.tar.xz

That's 6.6MB less, or 12.5%.

Comment 1

[(not currently active) Ted Mielczarek]

Some interesting analysis on flaws in the xz file format: http://www.nongnu.org/lzip/xz_inadequate.html

Comment 2

[Chris AtLee [:catlee]]

Interesting! Having signed manifests of the nightly's SHA-512 hash helps to verify integrity, but it would be better if the tool itself had better integrity checks.

Here are the sizes from a recent m-c nightly:

46701556 firefox-52.0a1.en-US.linux-x86_64.tar.xz-x86  # xz --x86 --lmza2=preset=9e
47585108 firefox-52.0a1.en-US.linux-x86_64.tar.xz      # xz -9e
47714090 firefox-52.0a1.en-US.linux-x86_64.tar.lz      # lzip -9
52974167 firefox-52.0a1.en-US.linux-x86_64.tar.zstd    # zstd -22
59371827 firefox-52.0a1.en-US.linux-x86_64.tar.bz2     # bzip2 (defaults to -9 I think)

The x86 / ARM filters with XZ are really nice.

Comment 3

[sjw]

A bunch of other projects like the kernel and Debian (dpkg) are already using xz. If you search for it you'll find some of their research about performance, compatibility and compression rate.

I also tested Googles Brotli, but that one is much slower and not yet widespread.