The though process for choosing this way of mirroring was

hdisk0 /1 used for primary are on 1 controller, hdisk4/5 are on other controller.
If we loose 1 controller or disk , primary and secondary PP would also be lost.

I am not sure how will this work, if the disk holding both Primary PP and Seconday PP's (although different copy) fails.

Are the PP's moved irrespective of whether it is primary or Secondary?