Date: Thu, 12 Jan 2006 07:01:38 -0600 From: Eric Anderson <anderson@centtech.com> To: Christoph Kukulies <kuku@www.kukulies.org> Cc: freebsd-hackers@freebsd.org Subject: Re: increasing dd disk to disk transfer rate Message-ID: <43C65332.6060009@centtech.com> In-Reply-To: <200601120948.k0C9mcqR092895@www.kukulies.org> References: <200601120948.k0C9mcqR092895@www.kukulies.org>
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Christoph Kukulies wrote: >My notebooks' hard disk, a Hitachi Travelstar 80 GB starts to develop read >errors. I have FreeBSD and Win XP on that disk. Although FreeBSD ist still >working , the errors in the Windows partition are causing Windows do ask for a >filesystem check nearly everytime I reboot the computer. One time the >error was in the hibernate.sys file, which impedes powering up quickly after >a hibernate. > >Anyway, I decided to buy a second identical hard disk and tried to >block by block copy the old disk to the new one using > >dd if=/dev/ad2 of=/dev/ad3 conv=noerror > > Specify a larger block size - the default is 512bytes, which is not efficient for what you are doing. Maybe 1mb would be the right number. >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. > >Any disk expert here? My motherboard is an ASUS P4S8X with an on board >promise controller (currently not in use). System disk is >on IDE1 and the two 80GB disks are master/slave on IDE2 bus. > > Also, put the disks on separate IDE busses - one disk on ide1, the other on ide2. This will help a lot.. >I wonder wether I could get better results (transfer rate) when attaching the >disks to copy to the promise IDE bus. > >And another question: > >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? > Not sure about that.. Eric -- ------------------------------------------------------------------------ Eric Anderson Sr. Systems Administrator Centaur Technology Anything that works is better than anything that doesn't. ------------------------------------------------------------------------
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