designating anyone of {HEAD ~ the plurality} of storage arrays as a primary device of {TAIL ~ the CSA} 
designating anyone of { HEAD ~ the plurality } of storage arrays as a primary device of { TAIL ~ the CSA }
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL