slow down dd - how?

David Kelly dkelly at
Thu Jul 8 17:05:08 UTC 2010

On Thu, Jul 08, 2010 at 06:44:38PM +0200, Roland Smith wrote:
> On Thu, Jul 08, 2010 at 05:50:52PM +0200, Jozsi Avadkan wrote:
> > How can I slow down dd?
> Play with the block size parameter (bs). Smaller block sizes means more
> reads. The default is 512 bytes, which is very small.
> > I don't want to slow down the pc, when generating a big file [~40
> > GByte].

I don't think Jozsi wants to burn more CPU cycles, just slow the
process. Perhaps to attract less attention? Or interfere less with other

Nice(1) is a good start but rtprio(1) is probably where he should look.

Also consider that writing a program of your own to serve as a slow pipe
shouldn't be very hard. Think it would be a good exercise as an
introduction to Unix programming. Simply copy stdin to stdout with a
usleep(3) between. Pipe dd through your slowpipe program.

Someone else has probably written a slow pipe. I haven't looked.

David Kelly N4HHE, dkelly at
Whom computers would destroy, they must first drive mad.

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