selecting at least some of the storage arrays, a combined available performance capability of which is at least equal to {HEAD ~ the performance requirements} for {TAIL ~ the logical data volume} 
for
selecting at least some of the storage arrays , a combined available performance capability of which is at least equal to { HEAD ~ the performance requirements } for { TAIL ~ the logical data volume }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL