>
> I don't understand: is this happening in my host ? Or is this happening
> inside the Qemu machine ?

Most likely inside the QEMU machine.

If you’re using ‘guix system vm-image’, you’ll have to pass

   --image-size=SIZE

where SIZE is the appropriate image size.  Failing to do that, the
command creates a small disk image and things don’t fit in it, hence
this error.

To determine what an appropriate size might be, you can do:

  guix size $(guix system build config.scm)

and then add maybe 10% to that (to account for the space taken by file
system metadata, the partition table, etc.)

That said, ‘guix system vm’ (not ‘vm-image’) should work out-of-the-box,
without having to specify --image-size.

HTH!

Ludo’.