fastest raw device copy?

[Christoph Kukulies]

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