Subject: Re: wedges vs. not-quite-wedges, was > 1T filesystems, disklabels, etc
To: Greywolf <greywolf@starwolf.com>
From: Christoph Hellwig <hch@infradead.org>
List: tech-kern
Date: 12/19/2002 20:18:31
On Thu, Dec 19, 2002 at 10:40:04AM -0800, Greywolf wrote:
> The big problem I see here is if the LVM data is kept in a config file
> somewhere and not anywhere on a disk, we can't ever realistically support
> LVM'd boot/root.  Will we ever be able to support alternate boot/root
> methods besides straight FFS?

What about the kernel doesn't care where the data is so it can be either
in some kind of disklabel _or_ a config file? :)

I know everyone here hates Linux examples, but you might want to look
at the linux device mapper, which basically is the kernel parts of the
wedges concept proposed here.

The devmapper pages itself and a volumemanager based on it:

	http://people.sistina.com/~thornber/

The code is in Linux 2.5, drivers/md/dm*, i.e.:

	http://oss.sgi.com/cgi-bin/cvsweb.cgi/linux-2.5-xfs/linux/drivers/md/

Userspace partition rading code for many disklabel types:

	http://lwn.net/Articles/13958/

A huge voulme management framework ontop of it (IMHO a bit bloated :)):

	http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/evms/evms2/engine/