Re: Curious unionfs-ro-mount for /gnu/store in installation-image

[Tobias Geerinckx-Rice <me@tobias.gr>]

Hartmut,

Hartmut Goebel wrote on 29/10/17 at 18:18:
> immediately after booting the installation image (build according to [1]
> and run according to [2]), the "mount" command spits out *two* unionfs
> mounted points:
[...]
> But I'm curious, where the second one comes from. I've been searching
> this for two or three hours now and did not find, where this is defined.

Running the same ‘mount’ command on my GuixSD returns a hint:

  nckx@apollo.tobias.gr ~$ mount
  /dev/mapper/root on / type ext4 (rw,relatime,data=ordered)
  /dev/mapper/root on /gnu/store type ext4 (ro,relatime,data=ordered)

> - gnu/system/install.scm defines the system to be put into the
> installation image. Thuns I thought it may be a file-system defined in
> install.scm. But related to the store there is only %immutable-store,
> which does not use unionfs a ro-bind-mount, not a unionfs.

I think this is all that's going on, and it's merely the output of
‘mount’ that's confusing you: the ‘ro’ bind mount ‘inherits’ the file
system type of the parent. In my example above, it's ext4. In yours,
it's fuse.unionfs.

Unless I'm missing something.

Kind regards,

T G-R