Subject: Re: compressed vnd, cgd and encryption
To: Hubert Feyrer <hubert@feyrer.de>
From: Daniel Carosone <dan@geek.com.au>
List: tech-kern
Date: 06/23/2006 22:16:39
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On Fri, Jun 23, 2006 at 09:54:05PM +1000, Daniel Carosone wrote:
> On Fri, Jun 23, 2006 at 09:47:13PM +1000, Daniel Carosone wrote:
> > cgd on vnd works
>=20
> but you wanted to know about vnd on cgd - this certainly also works.

and finally I get what you were concerned about: will this work
directly with vnd on the cgd device raw, without a filesystem in
between?  no. vnd will need a filesystem to hold the file, cgd or not.

However, you could use a pretty light-weight and simple filesystem in
the cgd, especially given you're going to be read-only. I suggest
cd9660 with the single vnd file inside.

Of course, you wanted all of this to start with a file on the client,
and you're still going to need that for the cgd, which means another
vnd.

So you'll wind up with:

 - makefs -t ffs
 - vndcompress
 - makefs -t cd9660
 - dd same file size
 - vnconfig
 - cgdconfig
 - dd cd9660 image into cgd

and on the client machine,
ffs-on-compressedvnd-on-cd9660-on-cgd-on-vnd.  Which will work, but
will probably also drive you batty.  What you really want is a
compressed filesystem you can mount from the cgd directly.  I don't
have any good suggestions for that, sorry.

What are you storing in here? Can you really not do the decompression
in userland, even counting tricks like gzexe?

--
Dan.



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