This is the answer.
Here is a similar post http://community.spiceworks.com/topic/240842-expanding-a-perc6-i-raid-10-array
Or would it be necessary to copy off the data, rebuild the entire array and restore?
This is the answer.
Here is a similar post http://community.spiceworks.com/topic/240842-expanding-a-perc6-i-raid-10-array