From owner-freebsd-hackers@FreeBSD.ORG Fri Jan 13 08:14:45 2006 Return-Path: X-Original-To: freebsd-hackers@freebsd.org Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 9656016A41F for ; Fri, 13 Jan 2006 08:14:45 +0000 (GMT) (envelope-from kuku@www.kukulies.org) Received: from www.kukulies.org (www.kukulies.org [213.146.112.180]) by mx1.FreeBSD.org (Postfix) with ESMTP id 8EBBA43D48 for ; Fri, 13 Jan 2006 08:14:44 +0000 (GMT) (envelope-from kuku@www.kukulies.org) Received: from www.kukulies.org (localhost [127.0.0.1]) by www.kukulies.org (8.13.3/8.12.10) with ESMTP id k0D8Edc6004555; Fri, 13 Jan 2006 09:14:40 +0100 (CET) (envelope-from kuku@www.kukulies.org) Received: (from kuku@localhost) by www.kukulies.org (8.13.3/8.12.10/Submit) id k0D8EcjE004554; Fri, 13 Jan 2006 09:14:38 +0100 (CET) (envelope-from kuku) Date: Fri, 13 Jan 2006 09:14:38 +0100 From: "Christoph P. Kukulies" To: Peter Jeremy Message-ID: <20060113081438.GA4401@kukulies.org> References: <200601120948.k0C9mcqR092895@www.kukulies.org> <20060112211300.GB13244@cirb503493.alcatel.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060112211300.GB13244@cirb503493.alcatel.com.au> User-Agent: Mutt/1.4.1i Cc: Christoph Kukulies , freebsd-hackers@freebsd.org Subject: Re: increasing dd disk to disk transfer rate X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 13 Jan 2006 08:14:45 -0000 Thanks, folks, for the interesting contributions. I really should have marked the subject "OT" but there spring up a lot of interesting ideas. On Fri, Jan 13, 2006 at 08:13:00AM +1100, Peter Jeremy wrote: > On Thu, 2006-Jan-12 10:48:38 +0100, Christoph Kukulies wrote: > >dd if=/dev/ad2 of=/dev/ad3 conv=noerror > > > >The process is running now since yesterday evening and it is at 53 MB > >at a transfer rate of about 1.1 MB/s. > > > >In case the the result being unusable I would like to find a way to make this > >copying faster. > > Note that whilst increasing the DD blocksize will speed up the > transfer, it will also increase the amount of collateral damage when a > hard error occurs. If you rummage around the ports or tools tree, > you'll find a utility (its name escapes me but I believe it was > written by phk) that is designed to do disk-to-disk recovery - it /usr/src/tools/tools/recoverdisk I fired up this tool yesterday night and it is still running. Ah yes, it runs forever unless it empties the queued failed block reads. It writes out a line of numbers (which are a bit difficult to understand). I think the suggestion to do a filewise recovery would be the best since it will be very unlikely > copys data in big slabs until it gets an error and then works around > the faulty area block by block. > > You should also install /usr/ports/sysutils/smartmontools - this > handles S.M.A.R.T. Yes, but what would smart help me further with recovery? > > >Is there a way to tweak the driver (be it the FreeBSD promise driver > >or the normal ata driver) to use more retries on errors so that I > >have the chance to copy everything or nearly everything of the already > >degrading hard disk? > > A quick look at the ata driver suggests that there are a number of > 'retry' and 'retries' variables/fields. I suspect you could increase > the number of retries if you wanted to patch the driver. Thanks for the help. -- Chris Christoph P. U. Kukulies kuku_at_kukulies.org