From owner-freebsd-fs@FreeBSD.ORG  Thu May 26 12:00:28 2011
Return-Path: <owner-freebsd-fs@FreeBSD.ORG>
Delivered-To: freebsd-fs@hub.freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id 55B27106571E
	for <freebsd-fs@hub.freebsd.org>; Thu, 26 May 2011 12:00:28 +0000 (UTC)
	(envelope-from gnats@FreeBSD.org)
Received: from freefall.freebsd.org (freefall.freebsd.org
	[IPv6:2001:4f8:fff6::28])
	by mx1.freebsd.org (Postfix) with ESMTP id E42768FC0A
	for <freebsd-fs@hub.freebsd.org>; Thu, 26 May 2011 12:00:27 +0000 (UTC)
Received: from freefall.freebsd.org (localhost [127.0.0.1])
	by freefall.freebsd.org (8.14.4/8.14.4) with ESMTP id p4QC0Rtx065173
	for <freebsd-fs@freefall.freebsd.org>; Thu, 26 May 2011 12:00:27 GMT
	(envelope-from gnats@freefall.freebsd.org)
Received: (from gnats@localhost)
	by freefall.freebsd.org (8.14.4/8.14.4/Submit) id p4QC0RLx065171;
	Thu, 26 May 2011 12:00:27 GMT (envelope-from gnats)
Date: Thu, 26 May 2011 12:00:27 GMT
Message-Id: <201105261200.p4QC0RLx065171@freefall.freebsd.org>
To: freebsd-fs@FreeBSD.org
From: Andriy Gapon <avg@FreeBSD.org>
Cc: 
Subject: Re: kern/153804: boot from zfs kernel.old recovery
	undocumented/impossible
X-BeenThere: freebsd-fs@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
Reply-To: Andriy Gapon <avg@FreeBSD.org>
List-Id: Filesystems <freebsd-fs.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-fs>,
	<mailto:freebsd-fs-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-fs>
List-Post: <mailto:freebsd-fs@freebsd.org>
List-Help: <mailto:freebsd-fs-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-fs>,
	<mailto:freebsd-fs-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Thu, 26 May 2011 12:00:28 -0000

The following reply was made to PR kern/153804; it has been noted by GNATS.

From: Andriy Gapon <avg@FreeBSD.org>
To: Pan Tsu <inyaoo@gmail.com>, bug-followup@FreeBSD.org,
        Nick Sayer <nsayer@kfu.com>
Cc:  
Subject: Re: kern/153804: boot from zfs kernel.old recovery undocumented/impossible
Date: Thu, 26 May 2011 14:54:53 +0300

 on 25/05/2011 11:52 Pan Tsu said the following:
 > Andriy Gapon <avg@FreeBSD.org> writes:
 > 
 >> Try the following options:
 >>
 >> 1)
 >> unload
 >> set kernel=kernel.old
 >> boot
 >>
 >> 2)
 >> unload
 >> load /boot/kernel.old/kernel
 >> load -t /boot/zfs/zpool.cache /boot/zfs/zpool.cache
 > 
 > zpool_cache_type can be anything. loader(8) unlike grub2 doesn't enforce
 > type to be "/boot/zfs/zpool.cache".
 
 Yes, one can specify load -t anything /boot/zfs/zpool.cache and it will work.
 I was just on the safe side following what's done in /boot/defaults/loader.conf.
 
 >> boot
 > 
 > Whatever happened to just typing following?
 > 
 >   boot kernel.old
 > 
 > It assumes zpool.cache was already preloaded by failed attempt to boot
 > default kernel. No need to `unload' the kernel, `boot' replaces it.
 > 
 
 Yes, I think that this command is a more convenient form of doing #1 above.
 
 All in all, I qualify this as a pilot error.
 Supported convenience methods do the right thing automatically.  In the completely
 manual method a user should know what he is doing.  Perhaps it's worth mentioning
 somewhere that zpool.cache must be loaded, but I think that it's a common knowledge.
 
 -- 
 Andriy Gapon