From owner-freebsd-questions@FreeBSD.ORG  Sun Mar  9 23:01:57 2008
Return-Path: <owner-freebsd-questions@FreeBSD.ORG>
Delivered-To: freebsd-questions@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id 05547106566C
	for <freebsd-questions@freebsd.org>;
	Sun,  9 Mar 2008 23:01:57 +0000 (UTC)
	(envelope-from jay@jcornwall.me.uk)
Received: from vps1.jcornwall.me.uk (vps1.jcornwall.me.uk [193.227.111.74])
	by mx1.freebsd.org (Postfix) with ESMTP id C70478FC18
	for <freebsd-questions@freebsd.org>;
	Sun,  9 Mar 2008 23:01:56 +0000 (UTC)
	(envelope-from jay@jcornwall.me.uk)
Received: from [192.168.1.3] (evilrealms.demon.co.uk [62.49.12.231])
	(using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits))
	(No client certificate requested)
	by vps1.jcornwall.me.uk (Postfix) with ESMTP id 95F025200EA
	for <freebsd-questions@freebsd.org>;
	Sun,  9 Mar 2008 23:01:55 +0000 (GMT)
Message-ID: <47D46C63.6060203@jcornwall.me.uk>
Date: Sun, 09 Mar 2008 23:01:55 +0000
From: "Jay L. T. Cornwall" <jay@jcornwall.me.uk>
User-Agent: Thunderbird 2.0.0.12 (Windows/20080213)
MIME-Version: 1.0
To: freebsd-questions@freebsd.org
References: <47D440EC.2080507@jcornwall.me.uk>
In-Reply-To: <47D440EC.2080507@jcornwall.me.uk>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Subject: Re: Read-only, diskless boot
X-BeenThere: freebsd-questions@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: User questions <freebsd-questions.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-questions>, 
	<mailto:freebsd-questions-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-questions>
List-Post: <mailto:freebsd-questions@freebsd.org>
List-Help: <mailto:freebsd-questions-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-questions>, 
	<mailto:freebsd-questions-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sun, 09 Mar 2008 23:01:57 -0000

Jay L. T. Cornwall wrote:

> All I need is:
>   * / partition to work in read-only mode.
>   * Volatile directories such as /root, /var and /tmp to be populated
>     into a memory filesystem on boot.

OK, this turned out to be easier after I spent some time reading through 
the /etc/rc.initdiskless script.

All that was needed was to create:
   /conf/base/root
   /conf/base/tmp
   /conf/base/var

And fill them with the files to be populated in a memory filesystem on 
reboot. A md_size file inside each dir tweaks the size of the memory 
disks according to the script.

Then touch /etc/diskless and the magic happens!

-- 
Jay L. T. Cornwall
http://www.jcornwall.me.uk/