Speed up package installation by using images instead of archives (like distri)?

[Mekeor Melire <mekeor@posteo.de>]

Hello Guix!

On the Guix-blog¹, Ludo already mentioned the lightning talk of Michael 
Stapelberg on the “distri” package manager which installs packages 
faster than common package managers by an order of magnitude.

Common package managers install a package by downloading it as an 
(compressed) archive and extracting the archive. But this extraction 
takes very long as it requires to create dozens of files on the file 
system which is an expensive IO operation.

In contrast, distri downloads the package as an (squashfs) image. That's 
it. The image will then be mounted (which is not an expensive IO 
operation) as a read-only virtual-file-system. (But as it's not 
recommendable to mount as many images as there are installed packages, 
distri mounts the package-images lazily, i.e. right before they are 
being used.)

(At least, the above explanation reflects my understanding.)

Thus, I wonder: (0) Does it make sense to make Guix follow this idea as 
well? I.e. should we make Guix install packages by downloading images 
and mounting those instead of extracting archives? (1) Does this even 
fit into Guix technically? I.e. how hard would it be to implement this? 
(2) And would it even be worth it? I.e. how much faster would Guix 
become?

I hope for an exciting discussion!


mekeor

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Footnotes:

   1: 
https://guix.gnu.org/en/blog/2021/getting-bytes-to-disk-more-quickly/