From owner-freebsd-stable@FreeBSD.ORG Fri Jan 25 21:18:23 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 358C216A419 for ; Fri, 25 Jan 2008 21:18:23 +0000 (UTC) (envelope-from cswiger@mac.com) Received: from mail-out3.apple.com (mail-out3.apple.com [17.254.13.22]) by mx1.freebsd.org (Postfix) with ESMTP id 1B96313C455 for ; Fri, 25 Jan 2008 21:18:22 +0000 (UTC) (envelope-from cswiger@mac.com) Received: from relay12.apple.com (relay12.apple.com [17.128.113.53]) by mail-out3.apple.com (Postfix) with ESMTP id 99B9D1F2FAA7; Fri, 25 Jan 2008 13:18:22 -0800 (PST) Received: from relay12.apple.com (unknown [127.0.0.1]) by relay12.apple.com (Symantec Mail Security) with ESMTP id 8DF71464004; Fri, 25 Jan 2008 13:18:22 -0800 (PST) X-AuditID: 11807135-9edeebb000004386-a2-479a521efda9 Received: from cswiger1.apple.com (cswiger1.apple.com [17.214.13.96]) by relay12.apple.com (Apple SCV relay) with ESMTP id 73EBE420008; Fri, 25 Jan 2008 13:18:22 -0800 (PST) Message-Id: <5D6C699B-A8D2-4ACD-A9F6-5CB263A88B42@mac.com> From: Chuck Swiger To: Thomas Hurst In-Reply-To: <20080125210527.GA40754@voi.aagh.net> Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (Apple Message framework v915) Date: Fri, 25 Jan 2008 13:18:22 -0800 References: <479A0731.6020405@skyrush.com> <20080125162940.GA38494@eos.sc1.parodius.com> <479A3764.6050800@skyrush.com> <3803988D-8D18-4E89-92EA-19BF62FD2395@mac.com> <20080125210527.GA40754@voi.aagh.net> X-Mailer: Apple Mail (2.915) X-Brightmail-Tracker: AAAAAA== Cc: Joe Peterson , freebsd-stable@freebsd.org Subject: Re: "ad0: TIMEOUT - WRITE_DMA" type errors with 7.0-RC1 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: Fri, 25 Jan 2008 21:18:23 -0000 On Jan 25, 2008, at 1:05 PM, Thomas Hurst wrote: >> These numbers are quite worrysome-- they should be zero or nearly >> so in a >> healthy drive. > > No, these are perfectly reasonable for a Seagate. I have about 12 > 7200.X's and all show the same sort of behavior. If they're nearly > zero > it's probably a sign your manufacturer isn't actually counting them > (marketroids hate accurate SMART readings). > > Try graphing them as counters; with an idle disk you'll see periodic > sawtooth patterns as the heads crawl from one side of the disk to the > other. SMART attributes which end with _Ct or _Count are supposed to increment with every event; things which end with _Rate (ie, Raw_Read_Error_Rate, Seek_Error_Rate) are supposed to indicate the frequency of such errors over time. It would be reasonable for Hardware_ECC_Recovered to keep the incremental count, but not the other two. I agree that minor periodic errors happen over time and are not a great concern, but a happy drive will show zero reallocated sectors, or perhaps a few over the span of a year or two, and will have a ECC recovered or UDMA_CRC count which is much smaller than was reported by Joe. YMMV, of course... -- -Chuck