From owner-freebsd-sparc64@FreeBSD.ORG Wed Jul 28 21:03:00 2010 Return-Path: Delivered-To: freebsd-sparc64@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 5B76C106567A; Wed, 28 Jul 2010 21:03:00 +0000 (UTC) (envelope-from marius@alchemy.franken.de) Received: from alchemy.franken.de (alchemy.franken.de [194.94.249.214]) by mx1.freebsd.org (Postfix) with ESMTP id E3E408FC20; Wed, 28 Jul 2010 21:02:59 +0000 (UTC) Received: from alchemy.franken.de (localhost [127.0.0.1]) by alchemy.franken.de (8.14.3/8.14.3/ALCHEMY.FRANKEN.DE) with ESMTP id o6SL2vrk013561; Wed, 28 Jul 2010 23:02:58 +0200 (CEST) (envelope-from marius@alchemy.franken.de) Received: (from marius@localhost) by alchemy.franken.de (8.14.3/8.14.3/Submit) id o6SL2v2F013560; Wed, 28 Jul 2010 23:02:57 +0200 (CEST) (envelope-from marius) Date: Wed, 28 Jul 2010 23:02:57 +0200 From: Marius Strobl To: John Baldwin Message-ID: <20100728210257.GB10197@alchemy.franken.de> References: <201007270945.32010.jhb@freebsd.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201007270945.32010.jhb@freebsd.org> User-Agent: Mutt/1.4.2.3i Cc: freebsd-sparc64@freebsd.org Subject: Re: ZFS root partition X-BeenThere: freebsd-sparc64@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Porting FreeBSD to the Sparc List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 28 Jul 2010 21:03:00 -0000 On Tue, Jul 27, 2010 at 09:45:31AM -0400, John Baldwin wrote: > On Tuesday, July 27, 2010 4:40:48 am Rob Farmer wrote: > > Is is possible to have a ZFS root with sparc64? I've used one of the > > guides on the wiki, http://wiki.freebsd.org/RootOnZFS/GPTZFSBoot, on > > amd64 and it worked fine, but that doesn't seem to apply, since the > > /boot/pmbr and /boot/gptzfsboot files don't exist on sparc64. > > Booting from a GPT isn't supported for OpenFirmware, so it doesn't work for > sparc64. > Looking at the description of the ZFS on-disk format it should be possible to implement something similar with the VTOC scheme though; the first-stage loader (8K max., we have no zero-stage on sparc64) probably should jump to something like a 1.5-stage loader located in the 3.5MB boot block area located after the ZFS uberblock and would need to know how to read ZFS in order to finally load /boot/loader. I haven't looked at how the GPT variant works in detail but I suspect most of the ZFS-specific actually could be recycled. The other missing part would be to teach some part (maybe GEOM_PART) how to write something to the ZFS boot block area. Any takers? :) Marius