From mboxrd@z Thu Jan 1 00:00:00 1970 From: Atila Subject: Re: Faulty drive data recovery Date: Fri, 26 Nov 2010 16:45:08 -0200 Message-ID: <4CF00034.4080600@dpf.gov.br> References: <4CED1B5F.8000700@dpf.gov.br> <4CED376A.40502@ngs.ru> <4CEFEE90.3030209@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=KOI8-R Content-Transfer-Encoding: 7bit Return-path: Received: from mailhost1.dpf.gov.br ([200.169.41.12]:10946 "EHLO mailhost1.dpf.gov.br" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754250Ab0KZSzt (ORCPT ); Fri, 26 Nov 2010 13:55:49 -0500 In-Reply-To: <4CEFEE90.3030209@kernel.org> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Tejun Heo Cc: Greg Freemyer , Artem Bokhan , linux-ide@vger.kernel.org Em 26/11/2010 15:29, Tejun Heo escreveu: > Hello, > > On 11/24/2010 06:00 PM, Greg Freemyer wrote: >>>>> HI, I'm trying to recover data from a damaged hard disk, which has >>>>> plenty of bad sectors, but also has many good ones. The problem is that >>>>> when a bad sector is found, the drive keeps trying to read it, instead >>>>> of giving up and just move on, so the average data read rate is around >>>>> 5Kb/s. With such rates, it will take more than an year to finish. Since >>>>> I'm using gnu ddrescue (which logs bad sectors, so one can try then >>>>> again later), my goal is not waste time with errors, leaving the retries >>>>> to a second round. >>>>> So, my first attempt was to drastically lower the timeouts in >>>>> libata-eh.c. It seems to have improved a little, but I'm not having more >>>>> than 12Kb/s. >>>>> Is there any way to minimize retries and make errors finish faster? > You can directly issue r/w commands using SGIO where you can control > retry and timeout explicitly. Hmm... it might be a good idea to allow > userland to set FAILFAST bit on a block device? Sounds like a great idea to me. I think it would become popular in forensics. I followed Artem Bokhan s' tip on timeout and tried Greg Freemyer s' on smartctl. Unfortunately this particular drive is only ATA-7, so scterc wasn't available. But is definitively good to know. I never played with SGIO before, but there is plenty of time to learn to use it before ddrescue can finish copying.:) Thank you all, Atila