From owner-freebsd-fs@FreeBSD.ORG  Tue Dec 22 00:01:52 2009
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 1D009106566B;
	Tue, 22 Dec 2009 00:01:52 +0000 (UTC)
	(envelope-from rwatson@FreeBSD.org)
Received: from cyrus.watson.org (cyrus.watson.org [65.122.17.42])
	by mx1.freebsd.org (Postfix) with ESMTP id ED6AF8FC18;
	Tue, 22 Dec 2009 00:01:51 +0000 (UTC)
Received: from fledge.watson.org (fledge.watson.org [65.122.17.41])
	by cyrus.watson.org (Postfix) with ESMTPS id 9140346B03;
	Mon, 21 Dec 2009 19:01:51 -0500 (EST)
Date: Tue, 22 Dec 2009 00:01:51 +0000 (GMT)
From: Robert Watson <rwatson@FreeBSD.org>
X-X-Sender: robert@fledge.watson.org
To: "Pedro F. Giffuni" <giffunip@tutopia.com>
In-Reply-To: <240049.46806.qm@web113517.mail.gq1.yahoo.com>
Message-ID: <alpine.BSF.2.00.0912220000360.73550@fledge.watson.org>
References: <712903.15604.qm@web113517.mail.gq1.yahoo.com>
	<3612709F-15CA-4A59-86B1-2674BAA2936D@gmail.com>
	<240049.46806.qm@web113517.mail.gq1.yahoo.com>
User-Agent: Alpine 2.00 (BSF 1167 2008-08-23)
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed
Cc: freebsd-fs@freebsd.org, jeff@FreeBSD.org
Subject: Re: Plans for Logged/Journaled UFS
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, 22 Dec 2009 00:01:52 -0000


On Mon, 21 Dec 2009, Pedro F. Giffuni wrote:

>> gjournal(8) journals everything, that is all data and metadata are 
>> journaled. Which can help with random writes, but essentially cuts linear 
>> write throughput in half.
>
> I recall ext3fs also journals everything by default and still is very 
> popular.
>
> I am asking because I've been playing a bit with Aditya's ext2fs (mostly 
> UFS1) and one of the ideas there is adding gjournal support instead of 
> starting from scratch.

I'm CC'ing Jeff Roberson, who perhaps can comment on his on-going project to 
merge journaling techniques with soft updates in UFS (which is just meta-data 
journaling, but hopefully will address many of the fsck/bgfsck-related 
concerns people have).

Robert N M Watson
Computer Laboratory
University of Cambridge