From owner-freebsd-questions@FreeBSD.ORG Thu Sep 27 19:22:32 2007 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 0E7BF16A419 for ; Thu, 27 Sep 2007 19:22:32 +0000 (UTC) (envelope-from cswiger@mac.com) Received: from mail-out4.apple.com (mail-out4.apple.com [17.254.13.23]) by mx1.freebsd.org (Postfix) with ESMTP id D632013C468 for ; Thu, 27 Sep 2007 19:22:31 +0000 (UTC) (envelope-from cswiger@mac.com) Received: from relay12.apple.com (relay12.apple.com [17.128.113.53]) by mail-out4.apple.com (Postfix) with ESMTP id D4819134A002; Thu, 27 Sep 2007 12:22:31 -0700 (PDT) Received: from relay12.apple.com (unknown [127.0.0.1]) by relay12.apple.com (Symantec Mail Security) with ESMTP id BA4C02804E; Thu, 27 Sep 2007 12:22:31 -0700 (PDT) X-AuditID: 11807135-a6700bb000006e40-ce-46fc02f7227b Received: from [17.214.13.96] (cswiger1.apple.com [17.214.13.96]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (No client certificate requested) by relay12.apple.com (Apple SCV relay) with ESMTP id 9A0672804C; Thu, 27 Sep 2007 12:22:31 -0700 (PDT) In-Reply-To: <20070927210423.K20243@wojtek.tensor.gdynia.pl> References: <001201c8012d$e747d620$0a00020a@mickey> <0079D5BC-57FB-4013-B772-545D7D83203B@mac.com> <20070927210423.K20243@wojtek.tensor.gdynia.pl> Mime-Version: 1.0 (Apple Message framework v752.2) Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Message-Id: Content-Transfer-Encoding: 7bit From: Chuck Swiger Date: Thu, 27 Sep 2007 12:22:30 -0700 To: Wojciech Puchar X-Mailer: Apple Mail (2.752.2) X-Brightmail-Tracker: AAAAAA== Cc: Don O'Neil , freebsd-questions@freebsd.org Subject: Re: Stress testing/burning in HDDs X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 27 Sep 2007 19:22:32 -0000 On Sep 27, 2007, at 12:04 PM, Wojciech Puchar wrote: >> It's reasonable to start with something like a: >> >> dd if=/dev/your_disk of=/dev/null bs=5120 >> >> ...to at least try reading every sector on the drive as a basic >> sanity check. > > why so small blocks of 10 sectors? > > i use bs=64k at least goes faster. Agreed, but he asked for a stress-test-- arguably, hitting with a size of 512 might be better for that purpose than anything faster. I chose 5120 because many ATA devices seem to have a maximum request/ DMA-transfer size of 16 sectors, and 512 * 10 is convenient and fits under that. -- -Chuck