guix weather -m etc/sources-manifest.scm and CI?

[zimoun <zimon.toutoune@gmail.com>]

Hi,

Playing with the new 'etc/sources-manifest.scm', using fb32a38, I get:

--8<---------------cut here---------------start------------->8---
$ guix weather -m ~/src/guix/guix/etc/source-manifest.scm
computing 16,831 package derivations for x86_64-linux...
looking for 16,831 store items on https://ci.guix.gnu.org...
https://ci.guix.gnu.org
  74.6% substitutes available (12,556 out of 16,831)
  at least 65,367.1 MiB of nars (compressed)
  81,988.1 MiB on disk (uncompressed)
  0.095 seconds per request (1,606.8 seconds in total)
  10.5 requests per second

  0.0% (0 out of 4,275) of the missing items are queued
  5 queued builds
      aarch64-linux: 4 (80.0%)
      powerpc64le-linux: 1 (20.0%)
  build rate: .00 builds per hour
      powerpc64le-linux: 0.00 builds per hour
      aarch64-linux: 0.00 builds per hour
      i686-linux: 0.00 builds per hour
      x86_64-linux: 0.00 builds per hour
looking for 16,831 store items on https://bordeaux.guix.gnu.org...
https://bordeaux.guix.gnu.org
  99.8% substitutes available (16,804 out of 16,831)
  62,195.0 MiB of nars (compressed)
  108,212.7 MiB on disk (uncompressed)
  0.049 seconds per request (829.2 seconds in total)
  20.3 requests per second
  (continuous integration information unavailable)
--8<---------------cut here---------------end--------------->8---

The questions are:

Why ci.guix.gnu.org contains only 75%?  And bordeaux almost everything?
(I guess the missing ones on bordeaux are corner cases as icecat, linux-libre).

Does it make sense to duplicate the storage of all these origins?

Using extensively "guix time-machine", I note that a lot of
derivations are missing and thus they are built locally, which is
costly on poor machine.  Could we reduce the duplication and so save
some space in order to systematically keep these derivations?  It
would greatly ease the Guix experience for "guix time-machine" users.
:-)

Cheers,
simon

PS: about etc/disarchive-manifest.scm, I guess 'all-origins' is missing:

--8<---------------cut here---------------start------------->8---
(let ((origins (all-origins)))
  (manifest
   (list (manifest-entry
           (name "disarchive-collection")
           (version (length origins))
           (item (disarchive-collection origins))))))
--8<---------------cut here---------------end--------------->8---