From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265878AbUBPTao (ORCPT ); Mon, 16 Feb 2004 14:30:44 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265876AbUBPTao (ORCPT ); Mon, 16 Feb 2004 14:30:44 -0500 Received: from 80-169-17-66.mesanetworks.net ([66.17.169.80]:54444 "EHLO mail.bounceswoosh.org") by vger.kernel.org with ESMTP id S265851AbUBPT1z (ORCPT ); Mon, 16 Feb 2004 14:27:55 -0500 Date: Mon, 16 Feb 2004 12:27:41 -0700 From: "Eric D. Mudama" To: Jeff Garzik Cc: Chip Salzenberg , Bartlomiej Zolnierkiewicz , Linux Kernel , Andrew Morton Subject: Re: Linux 2.6.3-rc3 - IDE DMA errors on Thinkpad A30 Message-ID: <20040216192741.GA22218@bounceswoosh.org> Mail-Followup-To: Jeff Garzik , Chip Salzenberg , Bartlomiej Zolnierkiewicz , Linux Kernel , Andrew Morton References: <200402151658.57710.bzolnier@elka.pw.edu.pl> <20040215163438.GC3789@perlsupport.com> <200402151808.42611.bzolnier@elka.pw.edu.pl> <20040216005523.GD3789@perlsupport.com> <40302783.6020505@pobox.com> <20040216033740.GE3789@perlsupport.com> <40303D59.4030605@pobox.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <40303D59.4030605@pobox.com> User-Agent: Mutt/1.5.5.1+cvs20040105i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Feb 15 at 22:47, Jeff Garzik wrote: >Chip Salzenberg wrote: >>Still: I wonder if the occasional bad sector is really that bad. >>Shirley, at the unreal densities of today's drives, the development of >>bad sectors is inevitable? (Especially in a laptop drive that's >>bounced around in normal use.) > >Open argument :) > >A lot of smart people will argue that a bad sector every now and again >occurs, and "I've run my server's disks that way for years." > >Other equally smart people argue that modern IDE disks reserve space for >remapping bad sectors. If you run out of sectors that the drive is >willing to silently remap for you, you should toss the disk and buy a >new one. Yes, definitely. There are a *lot* of spare sectors on a modern IDE drive -- Running out of spares is an extremely rare event, and usually indicates that the drive has been operating in severe conditions for its lifetime. (>55C + vibe sorts of things) >There is of course the caveat that it is impossible to avoid the drive >returning "bad sector", instead of silently remapping, on reads. Yes, because at that point, there's nothing to remap. If the drive couldn't read it, and knows it isn't in its 2/8MB cache, remapping is pointless until there is known-good data to apply. Therefore, only on the write is there a good reason to examine and possibly remap an LBA. >Oh, and I just thought of something else. Current Linux filesystems >will, on a read error, usually mark it as a bad sector and move on. >Really, they should attempt to write to the bad sector before >considering it bad. > >As a result, current kernels will AFAICT assume a sector is bad even >when the drive politely swaps a good sector in place for you. > >One for the todo list, I suppose... a useable workaround for this is >probably good ole 'e2fsck -c', i.e. badblocks... That says "check again >to see if this sector is bad", and -hopefully- will unmark bad blocks >that were incorrectly marked bad. Agreed. In most cases, a simpe write to the supposedly-defective LBA will get the drive to resolve whether it is a permanent media defect that needs to be remapped, or else functional media that has gone bad for some other reason. (of which there are several... excessive cold/heat, vibration, poor power, etc) -- Eric D. Mudama edmudama@mail.bounceswoosh.org