Date: Fri, 31 Oct 2008 16:48:32 +0100 From: Christoph Kukulies <kuku@kukulies.org> To: Jerry McAllister <jerrymc@msu.edu> Cc: freebsd-questions@freebsd.org Subject: Re: fastest raw device copy? Message-ID: <490B28D0.8070206@kukulies.org> In-Reply-To: <20081031153709.GC17878@gizmo.acns.msu.edu> References: <490AC650.3000904@kukulies.org> <20081031153709.GC17878@gizmo.acns.msu.edu>
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Jerry McAllister schrieb: > On Fri, Oct 31, 2008 at 09:48:16AM +0100, Christoph Kukulies wrote: > > >> Hi list, >> >> I'm considering using a bootable USB stick with FreeBSD to perform a >> backup of my notebooks' >> 500 GB hard disk to a physically identical (same make, same type, same >> size) hard disk attached to USB. >> >> 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 >> >> but maybe there is a utility which does this faster or a larger buffer >> size? Probably the limit will be >> the USB 2.0 bus speed anyway? >> > > Are you sure you want to do a sector-by-sector copy? > That won't get you much that is useful in terms of a backup. > > Can't you use dump/restore instead? > > Dump each file system on /dev/ad0 to a file on /dev/da0. > > Create a file system on /dev/da0 using newfs first. You may or > may not want to create a FreeBSD slice and partition there before > doing the newfs. > Make a mount point and mount it. > > mkdir /bkmnt > mount /dev/da0 /bkmnt Or if you created slice and partition in /dev/da0 > mount /dev/da0s1a /bkmnt > > Then do the dumps > > dump 0af /bkmnt/rootbackup / > dump 0af /bkmnt/usrbackup /usr > dump 0af /bkmnt/homehackup /home > > etc for whatever file systems you want to back up. > > You will be much better off than with a sector by sector copy. > > ////jerry > The idea was to have a drop in backup for my notebook that allows me to continue working with a minimum of delay. (requires a philips screwdriver though :-) Of course a failure of the source disk while doing the image copy as the worst case scenario would leave me with empty hands :-) There are a couple of partitions with different OSs on that hard drive. -- Christoph
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