Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751326AbWAVTvG (ORCPT ); Sun, 22 Jan 2006 14:51:06 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751320AbWAVTvG (ORCPT ); Sun, 22 Jan 2006 14:51:06 -0500 Received: from uproxy.gmail.com ([66.249.92.193]:56143 "EHLO uproxy.gmail.com") by vger.kernel.org with ESMTP id S1751326AbWAVTvF convert rfc822-to-8bit (ORCPT ); Sun, 22 Jan 2006 14:51:05 -0500 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:date:from:to:cc:subject:message-id:in-reply-to:references:x-mailer:mime-version:content-type:content-transfer-encoding; b=LNMxht1L0dJ1K7cCsiWGx+5qHSdQf+3vQ7BYHvfyO2DSGiACMW4PLO3kp+ByiLm4I6h+voAhSE31VG1aTb/IFbvzoAmFc/F6sBa8HhnrJh9KI9j/8X5qXlOQz63j+xtgMSVgVDJi32vLZC0MUIcNTil+3lZ0FKfChDv5xRvMxxg= Date: Sun, 22 Jan 2006 20:50:39 +0100 From: Diego Calleja To: "Theodore Ts'o" Cc: nigelenki@comcast.net, linux-kernel@vger.kernel.org Subject: Re: soft update vs journaling? Message-Id: <20060122205039.e8842bae.diegocg@gmail.com> In-Reply-To: <20060122093144.GA7127@thunk.org> References: <43D3295E.8040702@comcast.net> <20060122093144.GA7127@thunk.org> X-Mailer: Sylpheed version 2.1.9 (GTK+ 2.8.9; i486-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1659 Lines: 33 El Sun, 22 Jan 2006 04:31:44 -0500, Theodore Ts'o escribi?: > One major downside with Soft Updates that you haven't mentioned in > your note, is that the amount of complexity it adds to the filesystem > is tremendous; the filesystem has to keep track of a very complex > state machinery, with knowledge of about the ordering constraints of > each change to the filesystem and how to "back out" parts of the > change when that becomes necessary. And FreeBSD is implementing journaling for UFS and getting rid of softupdates [1]. While this not proves that softupdates is "a bad idea", i think this proves why the added sofupdates complexity doesn't seem to pay off in the real world. [1]: http://lists.freebsd.org/pipermail/freebsd-hackers/2004-December/009261.html "4. Journaled filesystem. While we can debate the merits of speed and data integrety of journalling vs. softupdates, the simple fact remains that softupdates still requires a fsck run on recovery, and the multi-terabyte filesystems that are possible these days make fsck a very long and unpleasant experience, even with bg-fsck. There was work at some point at RPI to add journaling to UFS, but there hasn't been much status on that in a long time. There have also been proposals and works-in-progress to port JFS, ReiserFS, and XFS. Some of these efforts are still alive, but they need to be seen through to completion" - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/