From owner-freebsd-stable@FreeBSD.ORG  Fri Dec 27 16:24:46 2013
Return-Path: <owner-freebsd-stable@FreeBSD.ORG>
Delivered-To: freebsd-stable@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115])
 (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits))
 (No client certificate requested)
 by hub.freebsd.org (Postfix) with ESMTPS id 68BAD55B;
 Fri, 27 Dec 2013 16:24:46 +0000 (UTC)
Received: from mail-vc0-x229.google.com (mail-vc0-x229.google.com
 [IPv6:2607:f8b0:400c:c03::229])
 (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits))
 (No client certificate requested)
 by mx1.freebsd.org (Postfix) with ESMTPS id EB9571CA1;
 Fri, 27 Dec 2013 16:24:45 +0000 (UTC)
Received: by mail-vc0-f169.google.com with SMTP id hu19so4961925vcb.28
 for <multiple recipients>; Fri, 27 Dec 2013 08:24:45 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113;
 h=mime-version:in-reply-to:references:date:message-id:subject:from:to
 :cc:content-type;
 bh=9zdIpjN9w1XgaXsOw+6fN+7OPJ8oRzCjyYZZ96ZHRfw=;
 b=bxTQiq6G8cHONrFYXQShy3zTwQIbwwe/3fNntp+e+zgU4HW9EJiIM7VKZhsNyZ97wu
 QGzZsilY7RM3NfKzTzg4aq3GsFrpOgcdDn2CCnhUs4OooZiLq0zw+4GSIJcvpVse/AbA
 s2DbdbpDXTwe5ahcxg6X8UiqoT3X+AgFk7VdY++shkwC8N328VmyN1m7/cc2QJPZo9z4
 jbx0Oc3eMi0TdycGu48cBK3B1K2618umv6uopbDap2z0V9iyp5cXKEheTinT9jSkQm7B
 HH5TlA0LyWi65jaEYxxnA+evZpmLnR8L4ns3SfjkbgJTn5yWbfdzXuXp7WuPVhiZk5+e
 Ee6g==
MIME-Version: 1.0
X-Received: by 10.52.135.201 with SMTP id pu9mr22391567vdb.13.1388161484958;
 Fri, 27 Dec 2013 08:24:44 -0800 (PST)
Received: by 10.58.165.2 with HTTP; Fri, 27 Dec 2013 08:24:44 -0800 (PST)
In-Reply-To: <alpine.BSF.2.00.1312270859430.32365@wonkity.com>
References: <20131226162521.GK2009@glenbarber.us>
 <CA+WntOt26JXT3Bh8ccSM-fQ726c2Hy3F06n2iDbu3pLBXjn-AA@mail.gmail.com>
 <20131226212158.GD13109@glenbarber.us>
 <CACuV5sCjjsjFK9AjJ7saRPpDktwxf1rd6a-M2FKXXYf-EaBy2w@mail.gmail.com>
 <BCB09816844D0B52B1EFE964@atuin.in.mat.cc>
 <CACuV5sD2Cw=iZ=uE8BjcV6j8-Bc8ppChQ=ZPKZ7uFTXQLmhCxQ@mail.gmail.com>
 <2F6DABD655B7C3230EC0F15D@ogg.in.absolight.net>
 <CAB7-odmH-b=+_-BwF1jt7EMdTxpK-P+w+p6Ce9-k7mRvXpLzog@mail.gmail.com>
 <38B0C411B75D7482B92033D2@ogg.in.absolight.net>
 <alpine.BSF.2.00.1312270859430.32365@wonkity.com>
Date: Fri, 27 Dec 2013 11:24:44 -0500
Message-ID: <CAB7-od=i7xitXJU=-M+KLkH4iNw-mYbvZsMNjzitocfLB2ErLA@mail.gmail.com>
Subject: Re: FreeBSD 10.0-RC3 Now Available
From: Thomas Hoffmann <trh411@gmail.com>
To: Warren Block <wblock@wonkity.com>
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable
X-Content-Filtered-By: Mailman/MimeDel 2.1.17
Cc: Mathieu Arnold <mat@freebsd.org>,
 freebsd-current <freebsd-current@freebsd.org>, freebsd-stable@freebsd.org
X-BeenThere: freebsd-stable@freebsd.org
X-Mailman-Version: 2.1.17
Precedence: list
List-Id: Production branch of FreeBSD source code <freebsd-stable.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/options/freebsd-stable>,
 <mailto:freebsd-stable-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-stable/>
List-Post: <mailto:freebsd-stable@freebsd.org>
List-Help: <mailto:freebsd-stable-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-stable>,
 <mailto:freebsd-stable-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Fri, 27 Dec 2013 16:24:46 -0000

After I posted, it occurred to me to check out the
../bsdinstall/scripts/zfsboot  script to see how the boot code was laid
down when the MBR was created. It shows only:

dd if=3D/boot/zfsboot of=3D/dev/ada0s1 count =3D1

But, adding to my confusion, the FreeBSD wiki for ZFS on root (MBR-style)
shows something very close to what Mathieu suggested.

Unfortunately, I'm using an iMac with FreeBSD as the only OS. MBR is the
only way I can get it to boot after an install.

Looks like I've got some testing (and possible system restores) ahead of me=
.

Thanks.


On Fri, Dec 27, 2013 at 11:08 AM, Warren Block <wblock@wonkity.com> wrote:

> On Fri, 27 Dec 2013, Mathieu Arnold wrote:
>
>  +--On 27 d=E9cembre 2013 10:28:07 -0500 Thomas Hoffmann <trh411@gmail.co=
m>
>> wrote:
>> | All the examples I've seen for updating bootcode assume GPT. If one ha=
s
>> | MBR (as I do) and assuming the following basic scheme:
>> |
>> | gpart show ada0
>> | =3D>       63  976773105  ada0  MBR  (466G)
>> |          63  976773105     1  freebsd  [active]  (466G)
>> |
>> | gpart show ada0s1
>> | =3D>        0  976773105  ada0s1  BSD  (466G)
>> |           0  943218736       1  freebsd-zfs  (450G)
>> |   943218736   33554369       2  freebsd-swap  (16G)
>> |
>> | would the equivalent bootcode statement be:
>> |
>> | gpart bootcode -b /boot/pmbr -p /boot/zfsboot ada0s1
>>
>
> No, the PMBR is for GPT partitioning only.
>
>
>  | where the boot code is /boot/zfsboot (rather than /boot/gptzfsboot) an=
d
>> | ada0s1 is the slice on which FreeBSD is installed?
>>
>> Hum, no, if you're using MBR and not GPT, you can't use gpart,
>>
>
> Why not?  gpart is not GPT-specific.  It handles MBR and BSDlabel bootcod=
e
> correctly.
>
>
>  you have to
>> do something aweful like this :
>> # dd if=3D/boot/zfsboot of=3D/dev/ada0 count=3D1
>>
>
> That will overwrite the MBR partition table.
>
>
>  # sysctl kern.geom.debugflags=3D0x10
>> # dd if=3D/boot/zfsboot of=3D/dev/ada0 skip=3D1 seek=3D1024
>>
>
> That seems dangerous.  I have not tried with zfsboot, but this should be
> close:
>
>   # gpart bootcode -b /boot/zfsboot ada0
>   # gpart bootcode -b /boot/zfsboot ada0s1
>
> Untested!  The first one may need to use /boot/mbr.  A better way to do
> this, provided the system does not have a broken BIOS, would be to backup=
,
> repartition with GPT, and restore, avoiding the complication of multiple
> partitioning schemes.