From owner-freebsd-current Thu Sep 26 12:13:26 2002 Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.FreeBSD.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 25C0037B401 for ; Thu, 26 Sep 2002 12:13:24 -0700 (PDT) Received: from mailout04.sul.t-online.com (mailout04.sul.t-online.com [194.25.134.18]) by mx1.FreeBSD.org (Postfix) with ESMTP id 40A4443E3B for ; Thu, 26 Sep 2002 12:13:23 -0700 (PDT) (envelope-from Alexander@Leidinger.net) Received: from fwd02.sul.t-online.de by mailout04.sul.t-online.com with smtp id 17ue1L-0000Z3-06; Thu, 26 Sep 2002 21:09:55 +0200 Received: from Andro-Beta.Leidinger.net (520065502893-0001@[217.83.27.104]) by fmrl02.sul.t-online.com with esmtp id 17ue1F-0KywNcC; Thu, 26 Sep 2002 21:09:49 +0200 Received: from Magelan.Leidinger.net (Magelan [192.168.1.1]) by Andro-Beta.Leidinger.net (8.12.5/8.12.5) with ESMTP id g8QJ9mZq074359; Thu, 26 Sep 2002 21:09:48 +0200 (CEST) (envelope-from Alexander@Leidinger.net) Received: from Magelan.Leidinger.net (netchild@localhost [127.0.0.1]) by Magelan.Leidinger.net (8.12.5/8.12.5) with SMTP id g8QJ9lYO034095; Thu, 26 Sep 2002 21:09:48 +0200 (CEST) (envelope-from Alexander@Leidinger.net) Date: Thu, 26 Sep 2002 21:09:47 +0200 From: Alexander Leidinger To: Terry Lambert Cc: freebsd-current@FreeBSD.ORG Subject: Re: Journaled filesystem in CURRENT Message-Id: <20020926210947.5d5fdd45.Alexander@Leidinger.net> In-Reply-To: <3D93459B.E4405568@mindspring.com> References: <200209251319.g8PDJYoD047918@ib.com.ua> <20020925111232.B3686@Odin.AC.HMC.Edu> <20020926111949.5c0da160.Alexander@Leidinger.net> <20020926090325.A24614@zardoc.esmtp.org> <3D93459B.E4405568@mindspring.com> Organization: Independend X-Mailer: Sylpheed version 0.8.1claws (GTK+ 1.2.10; i386-portbld-freebsd5.0) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Sender: 520065502893-0001@t-dialin.net Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On Thu, 26 Sep 2002 10:36:27 -0700 Terry Lambert wrote: > That said, journalling and Soft Updates are totally orthogonal > technologies, just as btree and linear directory structures are > two orthogonal things. > > Journalling has advantages that a non-journalling FS with soft > updates does not -- can not -- have, particularly since it is > not possible to distinguish a power failure from a hardware > failure from (some) software failures, and those cases need to Power failure: No problem for both. Hardware failure (I assume you think about a HDD failure): Read failure: doesn't matter here Write failure: either the sector gets remapped (no problem for both), or the disk is in self destruct mode (both can't cope with this) Software failure: Are you talking about bugs in the FS code? Or about a nasty person which writes some bad data into the FS structures? > be treated differently for the purposes of recovery. The soft Sorry, I don't get it. Can you please be more verbose? > updates background recover can not do this; the foregound > recovery can, but only if it's not the abbreviated version. A What are you talking about? Did you managed to get an unexpected softupdates inconsistency after the last bugfix? I don't see a difference in the power or hardware failure cases for a journaled fs and SO. The only reason for a fg-fsck instead of a bg-fsck (in the "there's no bug in the bg-fsck code path" case) is if someone damages the fs-structures on disk (I assume there are no bugs in SO anymore which result in an unexpected SO inconsistency). Note: I don't think the actual code path for bg-fsck is bugfree at the moment (read: I don't trust it at the moment). > JFS that journals both data and metadata can recover from all > three, to a consistant state, and one that journals only > metadata can recover from two of them. SO writes the data directly to free sectors in the target filesystem. I don't see where journaled data is an improvement in fs-consistency here. Bye, Alexander. -- It's not a bug, it's tradition! http://www.Leidinger.net Alexander @ Leidinger.net GPG fingerprint = C518 BC70 E67F 143F BE91 3365 79E2 9C60 B006 3FE7 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message