The logical data volumes typically have {HEAD ~ performance requirements} that cannot be met by {TAIL ~ a single storage array} 
The logical data volumes typically have { HEAD ~ performance requirements } that can not be met by { TAIL ~ a single storage array }
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL