Booting From an Alternate Disk in a Mirrored ZFS Root Pool

Following this guide I created a mirror disk for my zroot.
So, I decided to disconnect the main zroot disk to see if the other one was booting (I installed the bootcode on the disc).
When the system boot, ZFS cannot boot the mirrored disk and display just a series of writing errors as :

ZFS WARNING : Unable to open gpt/zfs1 for writing (error=1)

and ends up at the prompt :

thanks -- i thought that "sudo gpart bootcode -b /boot/pmbr -p /boot/gptzfsboot -i 1 ada1" was creating a bootable drive!
So... I have managed to create mirrored ZFS zroot pool and the main drive will I can reboot from the mirrored one?
Sorry -- I am an idiot . It works.
The problem was that i changed the IDE node number on VMware and it was not placed under the correct one. (1:0 instead after deleting the main disk i moved to IDE 0:0). So it was searching on the wrong disk.

Now the status is rightly degraded as it should after a disk failure.