[bug#27401] Guessing the disk image size in 'guix system'

[Ludovic Courtès]

address@hidden (Ludovic Courtès) skribis:

> We can do “guix size $(guix system build foo.scm)” and add 10% or so to
> that.
>
> Maybe something like this mostly-untested patch would work?

I’ve committed a variant of this patch as
a8ac4f081a9a679498ea42ccfe001f218bba3043.

I’ve tested it with several OS configs and it worked, except for
“lightweight-desktop.tmpl” where it failed with a confusing GRUB error
that might have been caused by ENOSPC.

Feedback and suggestion to improve the estimate welcome!

Ludo’.