Subject: Re: Optimal block size for dd
To: Michael Blake <>
From: Luke Mewburn <>
List: netbsd-users
Date: 08/31/2003 12:52:21
On Sat, Aug 30, 2003 at 06:42:53PM +0100, Michael Blake wrote:
  | Hi All
  | I'm trying to make an image of a NTFS partition, and wondered what
  | the optimal block size is. I've tried 512B, but it seems really
  | slow...

I use bs=64k and that saturates the disk.

I actually use something like
	dd if=/dev/rwd0h bs=64k | gzip -1 > diskimage.gz
to reduce the image size by ~ 40%.

I found  gzip -9  and  bzip2 -N  don't save that much extra space
in these images, yet take significantly more time.