From owner-cvs-src@FreeBSD.ORG Thu Jul 22 17:15:07 2004 Return-Path: Delivered-To: cvs-src@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 0E53616A4CE; Thu, 22 Jul 2004 17:15:06 +0000 (GMT) Received: from pooker.samsco.org (pooker.samsco.org [168.103.85.57]) by mx1.FreeBSD.org (Postfix) with ESMTP id 8B70F43D41; Thu, 22 Jul 2004 17:15:06 +0000 (GMT) (envelope-from scottl@freebsd.org) Received: from [192.168.0.12] (g4.samsco.home [192.168.0.12]) (authenticated bits=0) by pooker.samsco.org (8.12.11/8.12.10) with ESMTP id i6MHL3vj067859; Thu, 22 Jul 2004 11:21:04 -0600 (MDT) (envelope-from scottl@freebsd.org) Message-ID: <40FFF5C0.9040905@freebsd.org> Date: Thu, 22 Jul 2004 11:13:36 -0600 From: Scott Long User-Agent: Mozilla/5.0 (Macintosh; U; PPC Mac OS X Mach-O; en-US; rv:1.7) Gecko/20040514 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Johan Pettersson References: <200407212045.i6LKjHvX090599@palm.tree.com> <40FEE569.2010209@elischer.org> <40FEE6CA.3090005@samsco.org> <20040722092441.GH3001@cirb503493.alcatel.com.au> <40FFC4CD.4080706@samsco.org> <20040722190318.5fe349d3.manlix@demonized.net> In-Reply-To: <20040722190318.5fe349d3.manlix@demonized.net> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Status: No, hits=0.0 required=3.8 tests=none autolearn=no version=2.63 X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on pooker.samsco.org cc: PeterJeremy@optushome.com.au cc: Scott Long cc: src-committers@freebsd.org cc: cvs-all@freebsd.org cc: cvs-src@freebsd.org Subject: Re: cvs commit: src/sys/kern kern_shutdown.c X-BeenThere: cvs-src@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: CVS commit messages for the src tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 22 Jul 2004 17:15:07 -0000 Johan Pettersson wrote: > On Thu, 22 Jul 2004 07:44:45 -0600 > Scott Long wrote: > > >>Peter Jeremy wrote: >> >>>On Wed, 2004-Jul-21 15:57:30 -0600, Scott Long wrote: >>> >>> >>>>Implementing a journalling filesystem would be a much more >>> >>>beneficial>use of time here. >>> >>> >>>You still wind up with unwritten data in RAM, just less of it. >>> >>>How much effort would be required to add journalling to UFS or UFS2? >>>How big a gain does journalling give you over soft-updates? >>> >> >>That's a very good question. A group at RPI has been working on it >>for some time, but I'm not sure how close they are to having it done. >>If you look in the commercial world, Apple, Sun, and Wasabi/NetBSD >>have all done it successfully (Wasabi's isn't open source, btw). My >>guess is that it would take about 4-5 months to get it going, and then >>at least 8-12 months to ensure that there are no bugs and to tune >>performance. Certainly not impossible, but not something that would be >>production quality on short notice. I think that you would also have >>to make it othogonal to softupdates. >> >>The gain that you get is that your filesystem recovery time drops >>tremendously. You also have a much better chance of all of the >>metadata being on the disk and recoverable. Furthermore, it opens the >>door for data+metadata journalling for even more protection (at a >>large cost to speed and/or buffer-cache pressure, of course). >> >>Scott > > > Isn't there ongoing work to port XFS to FreeBSD? There was, but it seems to have stalled due to lack of time by the person who was doing it. Also, the XFS port would have GPL licensing issues and therefor isn't suitable for everyone. Scott