On Fri, 12 Sep 2014 15:53:19 -0600, Joseph wrote:

> I have two identical HD in a box and want to duplicate sda to sdb
> I want sdb to be bootable just in case something happens to sda so I
> can swap the drives and boot.
> 
> Do I boot from USB and run:
> dd if=/dev/sda of=/dev/sdb bs=512 count=1

If you remove the cunt argument as already mentioned, this will copy the
whole drive, but it will be incredibly slow unless you add bs=4k. It also
only copies it once, as soon as you start using sda, sdb will be out of
date. Set up a RAID-1 array with the two drives, then install GRUB to the
boot sector of each drive, using grub2-install and you will always be
able to boot in the event of a failure of either drive.


-- 
Neil Bothwick

Always proofread carefully to see if you any words out.