Subject: Re: cp, cat performance problems?
To: Mike Cheponis <mac@Wireless.Com>
From: Charles M. Hannum <firstname.lastname@example.org>
Date: 03/31/2001 14:36:10
On Sat, Mar 31, 2001 at 01:59:20PM -0800, Mike Cheponis wrote:
> Why is the performance of "cp" and "cat" so poor compared with "dd"? -Mike
> # time dd if=/dev/rwd0e of=1g bs=4096k count=256
> # time cp 1g 1g.cp
> # time cat 1g>1g.cat
> # time dd if=1g of=1g.dd bs=4096k
The primary difference is that, because dd is using a much larger block
size, it can do much more I/O between disk seeks.