Convert standalone zpool to RAID1 with data in place

[Fox F]

Hello,

My intention is to have a zpool with two drives (1TB and 2TB) striped. I 
suppose I'd create it as such:

zpool create zp_test disk1 disk2

I would then create a zfs filesystem on that zpool and add data to it.

Then, I would want to mirror this data on another identical striped vdev.

The question is, what is the order of operations for creating the second 
striped vdev and adding it as a mirror to the first one, and how do I do 
that in such a way that the data on disk1/2 gets mirrored to the new 
addition?

I hope I am making sense.

-F