From owner-freebsd-stable@FreeBSD.ORG Sun Mar 31 21:02:26 2013 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.FreeBSD.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id F047616C; Sun, 31 Mar 2013 21:02:26 +0000 (UTC) (envelope-from scottl@samsco.org) Received: from pooker.samsco.org (pooker.samsco.org [168.103.85.57]) by mx1.freebsd.org (Postfix) with ESMTP id A6780F00; Sun, 31 Mar 2013 21:02:26 +0000 (UTC) Received: from [127.0.0.1] (Scott4long@pooker.samsco.org [168.103.85.57]) (authenticated bits=0) by pooker.samsco.org (8.14.5/8.14.5) with ESMTP id r2VL29hN079467; Sun, 31 Mar 2013 15:02:10 -0600 (MDT) (envelope-from scottl@samsco.org) Content-Type: text/plain; charset=iso-8859-1 Mime-Version: 1.0 (Mac OS X Mail 6.3 \(1503\)) Subject: Re: Any objections/comments on axing out old ATA stack? From: Scott Long In-Reply-To: <20130331130409.GO3178@equilibrium.bsdes.net> Date: Sun, 31 Mar 2013 15:02:09 -0600 Content-Transfer-Encoding: quoted-printable Message-Id: References: <51536306.5030907@FreeBSD.org> <20130331130409.GO3178@equilibrium.bsdes.net> To: Victor Balada Diaz , Alexander Motin X-Mailer: Apple Mail (2.1503) X-Spam-Status: No, score=-50.0 required=3.8 tests=ALL_TRUSTED, T_RP_MATCHES_RCVD autolearn=unavailable version=3.3.0 X-Spam-Checker-Version: SpamAssassin 3.3.0 (2010-01-18) on pooker.samsco.org Cc: "freebsd-current@freebsd.org FreeBSD" , "freebsd-stable@freebsd.org Stable" X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 31 Mar 2013 21:02:27 -0000 On Mar 31, 2013, at 7:04 AM, Victor Balada Diaz = wrote: > On Wed, Mar 27, 2013 at 11:22:14PM +0200, Alexander Motin wrote: >> Hi. >>=20 >> Since FreeBSD 9.0 we are successfully running on the new CAM-based = ATA=20 >> stack, using only some controller drivers of old ata(4) by having=20 >> `options ATA_CAM` enabled in all kernels by default. I have a wish to=20= >> drop non-ATA_CAM ata(4) code, unused since that time from the head=20 >> branch to allow further ATA code cleanup. >>=20 >> Does any one here still uses legacy ATA stack (kernel explicitly = built=20 >> without `options ATA_CAM`) for some reason, for example as workaround=20= >> for some regression? Does anybody have good ideas why we should not = drop=20 >> it now? >=20 > Hello, >=20 > At my previous job we had troubles with NCQ on some controllers. It = caused > failures and silent data corruption. As old ata code didn't use NCQ we = just used > it. >=20 > I reported some of the problems on 8.2[1] but the problem existed with = 8.3. >=20 > I no longer have access to those systems, so i don't know if the = problem > still exists or have been fixed on newer versions. >=20 > Regards. > Victor. So what I hear you and Matthias saying, I believe, is that it should be = easier to force disks to fall back to non-NCQ mode, and/or have a more responsive black-list for problematic controllers. Would this help the situation? = It's hard to justify holding back overall forward progress because of some bad = controllers; we do several Tbps off of AHCI controllers with NCQ enabled on FreeBSD = 9.x, enough to make up a sizable percentage of the internet's traffic, and we = see no problems. How can we move forward but also take care of you guys with problematic hardware? Scott