The logical data volume is, thus, formed across {TAIL ~ a number} of {HEAD ~ the storage} arrays 
The logical data volume is , thus , formed across { TAIL ~ a number } of { HEAD ~ the storage } arrays
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH