Date: Thu, 12 Jan 2006 16:20:29 -0500 From: Martin Cracauer <cracauer@cons.org> To: Christoph Kukulies <kuku@www.kukulies.org> Cc: freebsd-hackers@freebsd.org Subject: Re: increasing dd disk to disk transfer rate Message-ID: <20060112162029.A24320@cons.org> In-Reply-To: <200601120948.k0C9mcqR092895@www.kukulies.org>; from kuku@www.kukulies.org on Thu, Jan 12, 2006 at 10:48:38AM %2B0100 References: <200601120948.k0C9mcqR092895@www.kukulies.org>
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Moin moin, wie geht's :-) Christoph Kukulies wrote on Thu, Jan 12, 2006 at 10:48:38AM +0100: > > 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 > > The process is running now since yesterday evening and it is at 53 MB > at a transfer rate of about 1.1 MB/s. /usr/ports/mis/cstream is a dd-like tool which allows you to specify that it buffers up <n> megabyte of input before writing to the output. You need that because you are on the same bus with both disks. Use the -B and -b options with some high values. Experiment with the -c option. > 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? Just retrying the same block probably doesn't do it. You'll be more successful by seeking to move the head around before retrying. Martin -- %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Martin Cracauer <cracauer@cons.org> http://www.cons.org/cracauer/ FreeBSD - where you want to go, today. http://www.freebsd.org/
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