From owner-freebsd-stable@FreeBSD.ORG Tue Sep 12 11:26:37 2006 Return-Path: X-Original-To: freebsd-stable@freebsd.org Delivered-To: freebsd-stable@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 27BF016A403 for ; Tue, 12 Sep 2006 11:26:37 +0000 (UTC) (envelope-from xi@borderworlds.dk) Received: from ferengi.borderworlds.dk (ferengi.borderworlds.dk [80.166.152.7]) by mx1.FreeBSD.org (Postfix) with ESMTP id AF15543D45 for ; Tue, 12 Sep 2006 11:26:36 +0000 (GMT) (envelope-from xi@borderworlds.dk) Received: from dominion.borderworlds.dk (dominion.borderworlds.dk [10.1.0.10]) by ferengi.borderworlds.dk (Postfix) with ESMTP id D9826B817 for ; Tue, 12 Sep 2006 13:26:35 +0200 (CEST) Received: by dominion.borderworlds.dk (Postfix, from userid 2000) id 816718C8; Tue, 12 Sep 2006 13:26:35 +0200 (CEST) To: freebsd-stable@freebsd.org References: <45066E19.2040405@kuehlbox.de> From: Christian Laursen Date: Tue, 12 Sep 2006 13:26:35 +0200 In-Reply-To: (Ivan Voras's message of "Tue, 12 Sep 2006 12:59:13 +0200") Message-ID: User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.0.50 (berkeley-unix) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Subject: Re: gjournal and Softupdates X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 12 Sep 2006 11:26:37 -0000 Ivan Voras writes: > Christian Laursen wrote: >> Ivan Voras writes: >> >>> - todays desktop drives can lie about writing data. SoftUpdates relies >>> on some assumptions about when the data is physically written to >>> media, and those are not always valid today >> >> I think journaling relies on the same assumptions. > > Doesn't it rely less since a journal is written sequentially, but SU > expects ordering of many writes to different parts of the file system > to be persistent and in sequence? Journaling also needs writes to be done in the correct order. You don't want to write the real update to the filesystem before you have made sure that it has been committed to the journal. If that can happen you are no better off than without the journal. -- Christian Laursen