Date: Fri, 31 Oct 2008 11:37:09 -0400 From: Jerry McAllister <jerrymc@msu.edu> To: Christoph Kukulies <kuku@kukulies.org> Cc: freebsd-questions@freebsd.org Subject: Re: fastest raw device copy? Message-ID: <20081031153709.GC17878@gizmo.acns.msu.edu> In-Reply-To: <490AC650.3000904@kukulies.org> References: <490AC650.3000904@kukulies.org>
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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
>
> --
> Christoph
>
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