From owner-freebsd-fs@FreeBSD.ORG  Sat Jan 21 20:33:20 2012
Return-Path: <owner-freebsd-fs@FreeBSD.ORG>
Delivered-To: fs@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id 1545F1065670
	for <fs@freebsd.org>; Sat, 21 Jan 2012 20:33:20 +0000 (UTC)
	(envelope-from daniel@digsys.bg)
Received: from smtp-sofia.digsys.bg (smtp-sofia.digsys.bg [193.68.3.230])
	by mx1.freebsd.org (Postfix) with ESMTP id 939FA8FC08
	for <fs@freebsd.org>; Sat, 21 Jan 2012 20:33:18 +0000 (UTC)
Received: from digsys226-136.pip.digsys.bg (digsys226-136.pip.digsys.bg
	[193.68.136.226]) (authenticated bits=0)
	by smtp-sofia.digsys.bg (8.14.5/8.14.5) with ESMTP id q0LJvmU5087526
	(version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=NO);
	Sat, 21 Jan 2012 21:57:54 +0200 (EET)
	(envelope-from daniel@digsys.bg)
Mime-Version: 1.0 (Apple Message framework v1251.1)
Content-Type: text/plain; charset=iso-8859-1
From: Daniel Kalchev <daniel@digsys.bg>
In-Reply-To: <4F1B0177.8080909@digiware.nl>
Date: Sat, 21 Jan 2012 21:57:52 +0200
Content-Transfer-Encoding: quoted-printable
Message-Id: <AD03CC71-8142-4C2B-9FF5-F548EF377464@digsys.bg>
References: <4F193D90.9020703@digiware.nl> <20120121162906.0000518c@unknown>
	<4F1B0177.8080909@digiware.nl>
To: Willem Jan Withagen <wjw@digiware.nl>
X-Mailer: Apple Mail (2.1251.1)
Cc: Alexander Leidinger <Alexander@Leidinger.net>, fs@freebsd.org
Subject: Re: Question about  ZFS with log and cache on SSD with GPT
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: Sat, 21 Jan 2012 20:33:20 -0000


On Jan 21, 2012, at 8:18 PM, Willem Jan Withagen wrote:

> On 21-1-2012 16:29, Alexander Leidinger wrote:
>>>=20
>=20
>> See
>> =
http://www.leidinger.net/blog/2011/05/03/another-root-on-zfs-howto-optimiz=
ed-for-4k-sector-drives/
>> for a description how to align to 4k sectors. I do not know if the =
main
>> devices of the pool need to be setup with an emulated 4k size (the =
gnop
>> part in my description) or not, but I would assume all disks in the
>> pool needs to be setup with the temporary gnop setup.
>=20
> Well one way of resetting up the harddisks would be to remove them =
from
> the mirror each in turn. Repartion, and then rebuild the mirror, =
hoping
> that that would work, since I need some extra space to move the
> partitions up. :(

With ZFS, the 'alignment' is on per-vdev -- therefore you will need to =
recreate the mirror vdevs again using gnop to make them 4k aligned.=20

Only one disk in a vdev needs to be 'gnop-ed' to 4k sectors because ZFS =
uses the largest sector size from all devices in a vdev as the vdev =
'ashift' at creation time.

Daniel=