From owner-freebsd-stable@FreeBSD.ORG Fri Feb 20 11:53:13 2015 Return-Path: Delivered-To: stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id BCA30EAB for ; Fri, 20 Feb 2015 11:53:13 +0000 (UTC) Received: from mx0.gid.co.uk (mx0.gid.co.uk [194.32.164.250]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4914BDF9 for ; Fri, 20 Feb 2015 11:53:12 +0000 (UTC) Received: from [194.32.164.24] (80-46-130-69.static.dsl.as9105.com [80.46.130.69]) by mx0.gid.co.uk (8.14.2/8.14.2) with ESMTP id t1KBrBea048918; Fri, 20 Feb 2015 11:53:11 GMT (envelope-from rb@gid.co.uk) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 8.2 \(2070.6\)) Subject: Re: ada drives keep timing out! From: Bob Bishop In-Reply-To: <1BFD18FF-D3A7-4230-9425-CEDC7DC94181@tao.org.uk> Date: Fri, 20 Feb 2015 11:53:06 +0000 Content-Transfer-Encoding: quoted-printable Message-Id: References: <064CF905-DF19-40A7-8CE8-D9FFE17913EE@tao.org.uk> <938BC03E-2C47-4381-9D21-5849E9E6E126@gid.co.uk> <1BFD18FF-D3A7-4230-9425-CEDC7DC94181@tao.org.uk> To: Dr Josef Karthauser X-Mailer: Apple Mail (2.2070.6) Cc: stable@freebsd.org X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 20 Feb 2015 11:53:13 -0000 Hi, > On 20 Feb 2015, at 11:21, Dr Josef Karthauser wrote: >=20 >=20 >> On 20 Feb 2015, at 11:14, Bob Bishop wrote: >>=20 >> Hi, >>=20 >>> On 20 Feb 2015, at 10:34, Dr Josef Karthauser = wrote: >>>=20 >>> Hi there, >>>=20 >>> I reported this last year, but I=E2=80=99d like to revisit it as it = must have a software remedy. I know that I=E2=80=99m not the only one to = have reported the problem. >>>=20 >>> I have a ZFS pool with a number of western digital drives in it (WDC = WD1000FYPS-01ZKB0 02.01B01). >>=20 >> WD Green Power drives. I've had similar problems, sometimes they take = a looooong time to come ready; the controller times out waiting for = drive ready and the rest you know. >>=20 >> Depending on the controller there may be nothing you can do. Maybe = it's possible to turn off the drives's green features. I replaced the = drives with something that works.=20 >>=20 >=20 > Hi Bob, >=20 > In this case other report no such issues on the same hardware running = Linux, so it seems to me to be an internal timeout issue within FreeBSD, = or maybe Linux retries more than FreeBSD and so doesn=E2=80=99t = experience the issue that we do. It=E2=80=99s clear that FreeBSD is = proactively disconnecting the drive when the timeout occurs. So, maybe = there=E2=80=99s something that can be done there. It depends on the disk controller hardware/firmware (not the drive = electronics), not necessarily the driver. =46rom the drive datasheet = http://www.wdc.com/en/library/sata/2879-701236.pdf?wdc_lang=3Den "WD GreenPower drives monitor work load and automatically invoke idle = mode whenever possible to further reduce unnecessary power consumption. = Drive recovery time from idle mode is less than one second, [etc]" What happens is that the drive decides to idle and the controller has no = way of telling. So when the controller issues its next command, the = drive takes the best part of a second (if you are unlucky) to come out = of idle, execute the command and return to ready. The controller times = this out at a very low level and assumes that the drive has gone away. Maybe Linux does the equivalent of a bus rescan to work around this. I = had the problem using a dumb RAID 1 controller, once a drive dropped out = the mirror was broken so it was a big deal. > Joe -- Bob Bishop rb@gid.co.uk