From owner-freebsd-stable@FreeBSD.ORG Mon Sep 29 13:52:15 2008 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 5640D1065686 for ; Mon, 29 Sep 2008 13:52:15 +0000 (UTC) (envelope-from jdc@koitsu.dyndns.org) Received: from QMTA03.emeryville.ca.mail.comcast.net (qmta03.emeryville.ca.mail.comcast.net [76.96.30.32]) by mx1.freebsd.org (Postfix) with ESMTP id 36D0D8FC15 for ; Mon, 29 Sep 2008 13:52:15 +0000 (UTC) (envelope-from jdc@koitsu.dyndns.org) Received: from OMTA03.emeryville.ca.mail.comcast.net ([76.96.30.27]) by QMTA03.emeryville.ca.mail.comcast.net with comcast id Lay61a00J0b6N64A3dsEn6; Mon, 29 Sep 2008 13:52:14 +0000 Received: from koitsu.dyndns.org ([67.180.253.227]) by OMTA03.emeryville.ca.mail.comcast.net with comcast id LdsC1a00V4v8bD78PdsDek; Mon, 29 Sep 2008 13:52:13 +0000 X-Authority-Analysis: v=1.0 c=1 a=TxirYYpeSEAA:10 a=QO6ccaido9wA:10 a=6I5d2MoRAAAA:8 a=QycZ5dHgAAAA:8 a=qWPCJf9plI8tu1H20qwA:9 a=yXn4UqdH3LRhoTqbaqoA:7 a=n8r8LW2KJjAu1q9yVkT7t1me1PEA:4 a=EoioJ0NPDVgA:10 a=SV7veod9ZcQA:10 a=LY0hPdMaydYA:10 Received: by icarus.home.lan (Postfix, from userid 1000) id C513DC9437; Mon, 29 Sep 2008 06:52:12 -0700 (PDT) Date: Mon, 29 Sep 2008 06:52:12 -0700 From: Jeremy Chadwick To: Peter Jeremy Message-ID: <20080929135212.GA9553@icarus.home.lan> References: <20080921213426.GA13923@0lsen.net> <20080921215203.GC9494@icarus.home.lan> <20080921215930.GA25826@0lsen.net> <20080921220720.GA9847@icarus.home.lan> <249873145.20080926213341@takeda.tk> <20080927051413.GA42700@icarus.home.lan> <765067435.20080926223557@takeda.tk> <20080927064417.GA43638@icarus.home.lan> <20080927073616.GP15376@server.vk2pj.dyndns.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080927073616.GP15376@server.vk2pj.dyndns.org> User-Agent: Mutt/1.5.18 (2008-05-17) Cc: Derek Kuli??ski , freebsd-stable@freebsd.org, Clint Olsen Subject: Re: UNEXPECTED SOFT UPDATE INCONSISTENCY; RUN fsck MANUALLY 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: Mon, 29 Sep 2008 13:52:15 -0000 On Sat, Sep 27, 2008 at 05:36:17PM +1000, Peter Jeremy wrote: > On 2008-Sep-26 23:44:17 -0700, Jeremy Chadwick wrote: > >On Fri, Sep 26, 2008 at 10:35:57PM -0700, Derek Kuli??ski wrote: > >> As far as I know (at least ideally, when write caching is disabled) > ... > >FreeBSD atacontrol does not let you toggle such features (although "cap" > >will show you if feature is available and if it's enabled or not). > > True but it can be disabled via the loader tunable hw.ata.wc (at > least in theory - apparently some drives don't obey the cache disable > command to make them look better in benchmarks). Off-topic, but those who use it will be interested: hw.ata.wc has always been one of those "why was it done this way?!" features which has bothered me. It never made any sense to either disable or enable WC on all drives, since there's no guarantee the user will want that. With that kept in mind, I've submit a PR containing a small kernel patch, atacontrol patch, and update to the atacontrol man page that allows toggling of WC via "atacontrol wc on/off". http://www.freebsd.org/cgi/query-pr.cgi?pr=127717 Now users will have the ability to do "atacontrol wc on", enabling WC on drives of their choice. And yes, you can toggle on/off in real-time, regardless of what hw.ata.wc contains (that tunable just acts as a default). -- | Jeremy Chadwick jdc at parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, USA | | Making life hard for others since 1977. PGP: 4BD6C0CB |