From owner-freebsd-stable@FreeBSD.ORG Fri Jan 4 09:56:28 2008 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 922ED16A41A for ; Fri, 4 Jan 2008 09:56:28 +0000 (UTC) (envelope-from chris#@1command.com) Received: from mail.1command.com (mail.1command.com [75.160.109.226]) by mx1.freebsd.org (Postfix) with ESMTP id BF69E13C457 for ; Fri, 4 Jan 2008 09:56:27 +0000 (UTC) (envelope-from chris#@1command.com) Received: from mail.1command.com (localhost.1command.com [127.0.0.1]) by mail.1command.com (8.13.3/8.13.3) with ESMTP id m049uJXN021777; Fri, 4 Jan 2008 01:56:25 -0800 (PST) (envelope-from chris#@1command.com) Received: (from www@localhost) by mail.1command.com (8.13.3/8.13.3/Submit) id m049uJpj021776; Fri, 4 Jan 2008 01:56:19 -0800 (PST) (envelope-from chris#@1command.com) Received: from hitme.hitometer.net (hitme.hitometer.net [75.160.109.235]) by webmail.1command.com (H.R. Communications Messaging System) with HTTP; Fri, 04 Jan 2008 01:56:19 -0800 Message-ID: <20080104015619.w1qyx0b7wo8cc00g@webmail.1command.com> X-Priority: 3 (Normal) Date: Fri, 04 Jan 2008 01:56:19 -0800 From: "Chris H." To: Clifton Royston References: <20080102002651.r72jwx0pgk4000c8@webmail.1command.com> <20080102070518.ki0v7vxkgo0cossg@webmail.1command.com> <20080102111751.5huybrwosgs0ccos@newwebmail.jnielsen.net> <20080102112230.g7p1bj3sdck488g8@newwebmail.jnielsen.net> <20080102084743.xtecj951wogwws8w@webmail.1command.com> <20080103192526.GA18773@lava.net> In-Reply-To: <20080103192526.GA18773@lava.net> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format="flowed" Content-Disposition: inline Content-Transfer-Encoding: 7bit User-Agent: H.R. Communications Internet Messaging System (HCIMS) 4.1 Professional (not for redistribution) / FreeBSD-5.5 Cc: freebsd-stable@freebsd.org Subject: Re: gmirror on 7B4 X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 04 Jan 2008 09:56:28 -0000 Quoting Clifton Royston : > On Wed, Jan 02, 2008 at 08:47:43AM -0800, Chris H. wrote: >> Quoting John Nielsen : >> >> >I'm not sure I remember everything from earlier in this thread so I >> >don't know if it's relevant, BUT you can't boot from a gstripe volume >> >(or from a gconcat one AFAIK). Inferring from your fstab example >> >below it doesn't sound like you intend to but I just wanted to be >> >sure. >> >> Are you sure? I read that using gmirror requires /kernel to be located >> in the /boot slice and everything else (all other slices) can be mirrored >> safely. But in all my reading (man pages, FBSD handbook, asstd articles) >> I haven't seen anything indicating booting wasn't possible from a gstripe >> volume. > > Your current idea is backwards; you can boot from entirely mirrored > drives (i.e. RAID1) and I've been doing it since 5.3, but AFAIK it is > impossible to boot from a striped drive and I suspect will remain so > for a long time. > > One way to visualize this is to recognize that because the gmirror > information is stored at the very end of the lower-level GEOM object, > each of the raw drives in the mirrored set appears to be an perfectly > normal drive when reading it from its beginning; thus it is possible to > simply read it as a normal device during the earlier stages of boot > until GEOM and gmirror loads. With striping, however, the logical > content is spread out across multiple drives, so any one drive you try > to boot from has only 1/Nth of the relevant sectors. Indeed, and thank you for pointing out the obvious to me. :) I was almost immediately reminded of that after posting. :P But really, I appreciate your taking the time to /enlighten/ me. It /does/ help. Given the /wealth/ of information afforded to me here on the list, after proposing my intentions. It quickly occurred to me that I had developed quite a few misconceptions about GEOM and friends, and that I should have taken just a bit more time before leaping. In the final analysis, I think it would be /far/ more efficient if I simply blanked my current disk, and simply laid it out as I ultimately want it. Then simply unarc the root folders to their desired destinations from the most recent backups. Which kind of makes this thread a loop. As my initial question was why wasn't gMIRROR part of sysinstall. It's funny, I've spent over 2 decades running *BSD, and yet I never really spent much time obtaining intimate knowledge about the disk "construction". Oh, it's not that I know nothing about it. But rather, that once I determined the ultimate layout for my needs, I simply let sysinstall handle it. So other than needing to add disks and move/ re-create slices, I was done. But as I now revisit it, I discover I should probably spend a little more time acquainting myself with it. :) Thanks again for taking the time to respond. I appreciate it. Chris > > Does this help? > > -- Clifton > > > -- > Clifton Royston -- cliftonr@iandicomputing.com / cliftonr@lava.net > President - I and I Computing * http://www.iandicomputing.com/ > Custom programming, network design, systems and network consulting services > _______________________________________________ > freebsd-stable@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-stable > To unsubscribe, send any mail to "freebsd-stable-unsubscribe@freebsd.org" > -- panic: kernel trap (ignored)