From owner-freebsd-fs@FreeBSD.ORG  Tue Aug 31 12:19:51 2010
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 DE04610656BC
	for <freebsd-fs@freebsd.org>; Tue, 31 Aug 2010 12:19:51 +0000 (UTC)
	(envelope-from freebsd-fs@m.gmane.org)
Received: from lo.gmane.org (lo.gmane.org [80.91.229.12])
	by mx1.freebsd.org (Postfix) with ESMTP id 945368FC31
	for <freebsd-fs@freebsd.org>; Tue, 31 Aug 2010 12:19:51 +0000 (UTC)
Received: from list by lo.gmane.org with local (Exim 4.69)
	(envelope-from <freebsd-fs@m.gmane.org>) id 1OqPob-00058v-QQ
	for freebsd-fs@freebsd.org; Tue, 31 Aug 2010 14:19:49 +0200
Received: from lara.cc.fer.hr ([161.53.72.113])
	by main.gmane.org with esmtp (Gmexim 0.1 (Debian))
	id 1AlnuQ-0007hv-00
	for <freebsd-fs@freebsd.org>; Tue, 31 Aug 2010 14:19:49 +0200
Received: from ivoras by lara.cc.fer.hr with local (Gmexim 0.1 (Debian))
	id 1AlnuQ-0007hv-00
	for <freebsd-fs@freebsd.org>; Tue, 31 Aug 2010 14:19:49 +0200
X-Injected-Via-Gmane: http://gmane.org/
To: freebsd-fs@freebsd.org
From: Ivan Voras <ivoras@freebsd.org>
Date: Tue, 31 Aug 2010 14:19:41 +0200
Lines: 18
Message-ID: <i5is0s$i6h$1@dough.gmane.org>
References: <4C7CE2D0.40400@telus.net>
Mime-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
X-Complaints-To: usenet@dough.gmane.org
X-Gmane-NNTP-Posting-Host: lara.cc.fer.hr
User-Agent: Mozilla/5.0 (X11; U; FreeBSD amd64; en-US;
	rv:1.9.1.9) Gecko/20100518 Thunderbird/3.0.4
In-Reply-To: <4C7CE2D0.40400@telus.net>
X-Enigmail-Version: 1.0.1
Subject: Re: gjournal alignment on 4K sector advanced format drives
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: Tue, 31 Aug 2010 12:19:52 -0000

On 08/31/10 13:09, Carl wrote:

>
> Now I want to add gjournal to some of my partitions. It seems to me that
> I must also ensure the journal is aligned just as I've done with the
> data. So far, though, I have found no information as to how the
> journal's own filesystem layout works. Does it use fixed size
> blocks/fragments like the UFS2 data does? If so, what is its minimum
> addressable unit size? If it is smaller than 4KiB, we get journal
> misalignment and a performance loss, right? What must I do to ensure the
> journal is fully aligned?

gjournal writes its metadata throughout the journal in sector sizes (512 
bytes) so it cannot be aligned in this way.

For this you need a solution which will actually change the sector size, 
like gnop or my glabel patch.