Date: Fri, 31 Oct 2008 15:36:02 +0100 From: Christoph Kukulies <kuku@kukulies.org> To: Ivan Voras <ivoras@freebsd.org> Cc: freebsd-questions@freebsd.org Subject: Re: fastest raw device copy? Message-ID: <490B17D2.6010000@kukulies.org> In-Reply-To: <gef0dq$l8a$1@ger.gmane.org> References: <490AC650.3000904@kukulies.org> <20081031110159.GA30244@icarus.home.lan> <gef0dq$l8a$1@ger.gmane.org>
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Ivan Voras schrieb: > Jeremy Chadwick wrote: > >> On Fri, Oct 31, 2008 at 09:48:16AM +0100, Christoph Kukulies wrote: >> > > >>> What would be the fastest way to do that sector by sector copy? I'm >>> using dd right now, >>> >>> dd if=/dev/ad0 of=/dev/da0 bs=10000000 >>> > > >> On the flip side, your blocksize (bs) there is quite high for no good >> reason. I'd pick something more like bs=64k or bs=128k. The default >> (512) is too small for what you want, but 10MBytes is silly. >> > > Not only that, but "10000000" isn't even correct - it needs to be a > multiple of sector size. Generally, using suffixes will do the right thing: > > dd if=/dev/ad0 of=/dev/da0 bs=1m > > OK, I understand that 10000000 isn't good, I just thought it wouldn't harm. But if it is a transfer rate killer then I'd better think of typing ^C now. The command is running for 6 hours now. An idea how I can check the current amount of transfered byed alongside the running dd command? Or watch the current i/o rate? -- Christoph
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