If Arch Linux were to add repositories containing split debug packages
for all our x86_64 packages, this would obviously add a fair amount of
space to the mirror requirements. It could possibly double or triple the
size taken by non-data packages. I don't have real-world numbers for how
much space it would take up, but I do have some comparisons.

For my custom repo as a sample, which I do upload debug packages for, I
am using 2.9Gi of space, and 1.7Gi comes from debug packages.

On the other side of things, our biggest 2 official packages are cuda,
4137.96 MiB of proprietary blobs that aren't currently stripped and
therefore even if we did split it into a debug package it wouldn't
increase space usage at all, and kicad-library-3d, 5171.97 MiB of pure
data in /usr/share, which is not eligible for debug packages anyway.

A naive list of packages which would probably generate debug packages:

$ expac -H M '%m %n %a' | grep -v 'any$' | sort --human-numeric-sort
[...]
1109.50 MiB emscripten x86_64
1136.27 MiB python-tensorflow x86_64
1145.23 MiB python-tensorflow-opt x86_64
1286.69 MiB python-pytorch-cuda x86_64
1289.44 MiB python-pytorch-opt-cuda x86_64
1518.42 MiB ghc-static x86_64
2589.23 MiB python-tensorflow-cuda x86_64
2597.38 MiB python-tensorflow-opt-cuda x86_64
3757.68 MiB tensorflow-cuda x86_64
3765.75 MiB tensorflow-opt-cuda x86_64
4137.96 MiB cuda x86_64

(Basically all of the really big stuff is tensorflow/cuda/machine
learning bits. We could selectively disable debug packages for two
PKGBUILDs and avoid all the worst offenders, if we needed to. heh.)

Packages which definitely would not (there's some big, high-profile
packages here, and my custom repo doesn't reflect this sort of spread at
all):

$ expac -H M '%m %n %a' | grep -v 'any$' | sort --human-numeric-sort
[...]
1202.02 MiB texlive-fontsextra any
1307.98 MiB texlive-fontsextra any
2006.67 MiB 0ad-data any
3112.39 MiB nltk-data any
5171.97 MiB kicad-library-3d any

...

Anyway, providing these symbols would be generally desirable for users,
and ideally it would work opt-out to make it easier for users to get
access to them. It's something we've generally wanted to do, see for
example https://bugs.archlinux.org/task/38755
And it's possible we may actually, at long last, get around to
implementing this.

So, question to mirror admins: if Arch was to add debug repositories,
would you be okay syncing them? And should it be opt-in or opt out?

The answers to these questions will influence the direction I will take
in trying to devise a satisfactory resolution to this outstanding
infrastructure request. So I would love to get some input from the
people who would be affected by such a change.

--
Eli Schwartz
Bug Wrangler and Trusted User