fastest raw device copy?

[Erik Trulsson]

On Fri, Oct 31, 2008 at 03:36:02PM +0100, Christoph Kukulies wrote:
> 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?

Just type a ^T on the terminal dd is running on. This will send a SIGINFO to
dd which will cause it to print out that information to the terminal.




-- 
<Insert your favourite quote here.>
Erik Trulsson
ertr1013 at student.uu.se