First off, unless the servers have the exact same hardware this is a bad idea. If you still want to do it, I'd recommend you connect the new server's hard drive to the old server, and do something like this:
Code:
dd if=/dev/hda of=/dev/hdb
It will be relatively fast, and will be a perfect 1:1 copy. If connecting the new hard drive in the old computer is not feasible, you can make an image file like this:
Code:
dd if=/dev/hda of=/image
Transfer the file to a computer with the new hard drive in it, and
Code:
dd if=/image of=/dev/hda