One guy reportedly did this with cat:

# cat /dev/hda >/dev/hdb

The disks were 100% identical, important for such things as sector sizes, etc.

The paranoid way would be to make filesystem, mount the second disk, and use cp -r.

This is what I do when I add one disk and, fx. move the /usr or /home tree to the new disk

Atle

__________________
PS
All of the above is to be read as '... unless I am wrong'
ENDPS