GEOM virtual storage early alpha

[Ivan Voras]

As part of Google's Summer Of Code 2006, I've been working on a "virtual
storage" class for GEOM. The purpose of this class is to allow creating
a large virtual storage device backed up by physical storage devices of
smaller total size. The development home page for the project is
http://wikitest.freebsd.org/gvirstor (where you can download a 
convenient .tgz).

Gvirstor (under whatever name it will be when it's finished) is almost
done. The basic operation  and metadata are not expected to change, so I 
think this is a good time for wider exposure. Some minor functionality 
is still unimplemented, like "stop" command (from userland, not kldunload).

If anyone's interested, please help test the module. It can be
downloaded from the above web page (use the latest archive), or from
//depot/user/ivoras/gvirstor in P4.

Notes:
  - This is work in progress, not finished. Do not alert the media :)
  - This is a good time for feature requests (that fit in gvirstor's model).
  - Read the README (or the man page if you use P4) for instructions on 
how to use it.
  - This is made for RELENG_6, and only tested on i386. Bug reports are
welcome.
  - Sponsored by Google, mentor: Pawel Jakub Dawidek, pjd at freebsd.org
  - I'll make an official announcement when the project's done and ready
for use.