ZFS zfs mirror with isci drive

I've been considering, on setting up and connecting an isci drive as an mirror to my vdev. Now, I am curious on your thoughts, on if this is an insane idea that is nothing but trouble or what. Now, I have read up and sharing an isci target over the network can/will hog/overwhelm the network connection to the point of needing a dedicated network connection just for isci. I have seen some old posts recommending setting up a HAST setup would be a better idea. From my understanding (limited to what information I've read), HAST seems to be way overkill in the basic thought, and a disadvantage in that the secondary side would become the Primary.

To describe the setup I am envisioning, be 2 computers on the same network Master and Slave. The Slave computer is hosting the isci drive/device to the Master computer. The Master computer is setup as a simple mirror internally (2 drives in the Master computer) and the isci drive added into make the mirror a 3 way mirror. Unlike the HAST setup, the Slave computer (isci host) NEVER gets promoted, it is to always stay as a secondary device. With this setup being a mirror setup, even if the isci drive goes offline, it should just be brought back up to date once it comes online.
Search the forums for discussions about read and write performance. I'd expect write performance to be not very good.