From owner-freebsd-questions@FreeBSD.ORG Fri Mar 18 15:48:18 2005 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 376E816A4CE for ; Fri, 18 Mar 2005 15:48:18 +0000 (GMT) Received: from relay04.roc.ny.frontiernet.net (relay04.roc.ny.frontiernet.net [66.133.182.167]) by mx1.FreeBSD.org (Postfix) with ESMTP id C63CB43D1D for ; Fri, 18 Mar 2005 15:48:17 +0000 (GMT) (envelope-from drew@mykitchentable.net) Received: from filter08.roc.ny.frontiernet.net (filter08.roc.ny.frontiernet.net [66.133.183.75])45215358544; Fri, 18 Mar 2005 15:48:17 +0000 (UTC) Received: from relay04.roc.ny.frontiernet.net ([66.133.182.167]) [66.133.183.75]) (amavisd-new, port 10024) with LMTP id 28510-15-12; Fri, 18 Mar 2005 15:48:17 +0000 (UTC) Received: from blacklamb.mykitchentable.net (70-97-221-18.dsl2.elk.ca.frontiernet.net [70.97.221.18])EE3F8358247; Fri, 18 Mar 2005 15:48:14 +0000 (UTC) Received: from [165.107.42.217] (unknown [165.107.42.217]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by blacklamb.mykitchentable.net (Postfix) with ESMTP id E0A013BF3A0; Fri, 18 Mar 2005 07:48:13 -0800 (PST) Message-ID: <423AF81F.7070400@mykitchentable.net> Date: Fri, 18 Mar 2005 07:47:43 -0800 From: Drew Tomlinson User-Agent: Mozilla Thunderbird 1.0 (Windows/20041206) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Bob Johnson References: <423A4647.5000709@mykitchentable.net> <200503172323.27821.bob89@bobj.org> In-Reply-To: <200503172323.27821.bob89@bobj.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: by amavisd-new-20040701 (2.0) at filter08.roc.ny.frontiernet.net cc: freebsd-questions@freebsd.org Subject: Re: sbp, camcontrol, and Tagged Queuing X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 18 Mar 2005 15:48:18 -0000 On 3/17/2005 8:23 PM Bob Johnson wrote: >On Thursday 17 March 2005 10:08 pm, Drew Tomlinson wrote: > > >>I posted this a while back and am still having the same problem. Can >>anyone offer any insight as to if the sbp man page suggestion about tagged >>queuing is something I should try? Is there any risk of screwing up my >>drives by trying this? >> >> >Tagged queueing queues up multiple instructions for the drive simultaneously. >The drive then attempts to sort them out and execute them in optimum order. >Some drives that claim to support tagged queueing do not correctly do so, and >don't perform well when it is used (and may lose data). If you set the queue >size to one, as recommended in the passage you reference, then only one >instruction will be issued to the drive at time, and it will behave like a >drive without tagged queueing. It will do no harm to the drive. If the >drive correctly implements tagged queueing, this will slow down the drive, >but if it does not correctly implement it, then this may dramatically speed >up the drive (and make it more stable). I have an external drive that >manages 1.3 MBps transfers with queueing enabled, and 25 MBps transfers when >I set the queue size to one. > >As for whether it will help your specific problem, I don't know, but I can't >see how it would do any harm to test it. > >This issue is not specific to FreeBSD. Any OS that supports tagged queuing >has problems with some drives. > >- Bob > > Thank you for your explanation. I will try this later today when I am close to the console and post my results for anyone else that may experience this problem. Cheers, Drew >[...] > > > >>da2 and da3 are two IDE drives in a firewire enclosure. These are also >>the drives that come up "referenced" after restarting. What do these >>errors mean? How can I correct them? Is the following section from the >>sbp man page applicable to my situation? >> >>Some (broken) HDDs don't work well with tagged queuing. If you have prob- >>lems with such drives, try ``camcontrol [device id] tags -N 1'' to dis- >>able tagged queuing. >> >>Thanks for your help! >> >>Drew >>