From owner-freebsd-fs@FreeBSD.ORG  Mon Feb 28 22:18:04 2011
Return-Path: <owner-freebsd-fs@FreeBSD.ORG>
Delivered-To: freebsd-fs@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id 185241065672
	for <freebsd-fs@freebsd.org>; Mon, 28 Feb 2011 22:18:04 +0000 (UTC)
	(envelope-from am@raisa.eu.org)
Received: from raisa.eu.org (178-73-15-208.home.aster.pl [178.73.15.208])
	by mx1.freebsd.org (Postfix) with ESMTP id CA3078FC0A
	for <freebsd-fs@freebsd.org>; Mon, 28 Feb 2011 22:18:03 +0000 (UTC)
Received: from bolt.zol (nereis.pl [62.121.98.25])
	(using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits))
	(No client certificate requested)
	by raisa.eu.org (Postfix) with ESMTP id 15D7F244;
	Mon, 28 Feb 2011 21:08:48 +0100 (CET)
Content-Type: text/plain; charset=utf-8; format=flowed; delsp=yes
In-Reply-To: <4D6AAC9A.4000602@jrv.org>
References: <op.vn2iid1qk84lxj@arrow> <4D6AAC9A.4000602@jrv.org>
To: "James R. Van Artsdalen" <james-freebsd-fs2@jrv.org>
From: "Emil Smolenski" <am@raisa.eu.org>
Date: Mon, 28 Feb 2011 21:08:19 +0100
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Message-ID: <op.vrmp2hrck84lxj@bolt.zol>
User-Agent: Opera Mail/11.01 (FreeBSD)
Cc: freebsd-fs@freebsd.org
Subject: Re: [ZFS] Booting from zpool created on 4k-sector drive
X-BeenThere: freebsd-fs@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
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: Mon, 28 Feb 2011 22:18:04 -0000

On Sun, 27 Feb 2011 20:57:14 +0100, James R. Van Artsdalen
<james-freebsd-fs2@jrv.org> wrote:

> Emil Smolenski wrote:
>> Hello,
>>
>> There is a hack to force zpool creation with minimum sector size equal
>> to 4k:
>>
>> # gnop create -S 4096 ${DEV0}
>> # zpool create tank ${DEV0}.nop
>> # zpool export tank
>> # gnop destroy ${DEV0}.nop
>> # zpool import tank
>>
>> This change is permanent. The only possibility to change the value of
>> ashift is: zpool destroy/create and restoring pool from backup.
>
> Is ashift a property of the pool or a property of the device?

It is property of the ZFS pool. It is calculated when the pool is created
based on the sector size advertised by devices.

> I'm wonder about the disk replacement scenario, where the replacement
> disk cannot be smaller than the disk it replaces.

And the new disk must advertise sector size equal or smaller than
2**ashift of the existing pool.

-- 
am