To duplicate a disk I used the following: dd if=/dev/rsd2c of=/dev/rsd3c bs=32M seek=1 skip=1 conv=noerror
the bs=32M was picked because it was a large size, and the machine has lots of free memory. Watching the machine I could see the disk activity lights blinking alternately about once a second and looks like, what I would expect, that dd does blocking I/O. Is there any method of coping a disk or partition, or even a file that uses non-blocking I/O? Such a method should cut the time down by half. Also for dd the block size has always been a puzzle. Asking google gives various opinion, only agreeing that the number should be a power of two. I have always had the believe that a bigger size is never hurts as long as there is free memory available on the system. Would there not be a method for dd to calculate what an optimal block size would be given the free memory and devices used.
