Bug#592564: document unusual but supported file system configurations

[Luk Claes <luk@debian.org>]

On 08/11/2010 01:47 AM, Russ Allbery wrote:

> Debian supports /usr as a separate file system from /, /usr as a remote
> file system, and /, /usr, and /etc mounted read-only (unless you want to
> do something that obviously requires them to be read-write, like change
> configuration or install new packages).  However, I don't believe any of
> this is documented explicitly.

Note that upstreams are making it harder to really support a seperate
/usr. Most notable example is udev which uses /usr/share/misc/pci.ids.
It's not that udev is not functional without it, but it means that if we
support a seperate /usr, we need an extra udevadm invokation to include
them later. There will for sure be similar cases, where we need to go
through extra loops to really support a separate /usr.

Do we support /usr as a remote file system aka do people use it and is
it well tested?

I think it's a good idea to look into documenting what file system
configurations we do support. I'm unsure about how many we really do
support nor about how many we really want to support though as it seem
to get harder to support these.

Cheers

Luk