From owner-freebsd-stable@FreeBSD.ORG Tue Aug 21 05:46:20 2007 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 9BF3516A418 for ; Tue, 21 Aug 2007 05:46:20 +0000 (UTC) (envelope-from martin@gneto.com) Received: from proxy2.bredband.net (proxy2.bredband.net [195.54.101.72]) by mx1.freebsd.org (Postfix) with ESMTP id 5EFC313C459 for ; Tue, 21 Aug 2007 05:46:20 +0000 (UTC) (envelope-from martin@gneto.com) Received: from mailbox.gneto.com (83.227.181.30) by proxy2.bredband.net (7.3.127) id 46C9A3900003390F; Tue, 21 Aug 2007 07:25:15 +0200 Received: from euklides.gneto.com (euklides.gneto.com [192.168.10.11]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mailbox.gneto.com (Postfix) with ESMTP id A550528429; Tue, 21 Aug 2007 07:23:16 +0200 (CEST) Message-ID: <46CA7681.3070909@gneto.com> Date: Tue, 21 Aug 2007 07:22:09 +0200 From: Martin Nilsson User-Agent: Thunderbird 2.0.0.6 (X11/20070802) MIME-Version: 1.0 To: Artem Kuchin References: <028f01c7e37a$d8f441b0$0c00a8c0@Artem> In-Reply-To: <028f01c7e37a$d8f441b0$0c00a8c0@Artem> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: freebsd-stable@freebsd.org Subject: Re: A little story of failed raid5 (3ware 8000 series) 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: Tue, 21 Aug 2007 05:46:20 -0000 Artem Kuchin wrote: > But i don't understand how and why it happened. ONly 6 hours ago (a > night before) > all those files were backed up fine w/o any read error. And now, right > after replacing > the driver and starting rebuild it said that there are bad sectors all > over those file. > How come? That is what patrol read is intended to detect before it is a problem. In a RAID5 array the checksums are only used when reconstructing data, if you have a bad block in a checksum sector it will not be detected until a drive have failed and you try to rebuild the array, unfortunately at that time it is too late... Beware that OS software solutions like diskcheckd will not find this as it only reads the data, not the checksums, it must be done on the controller. Regards, Martin