The present invention is storage apparatus where an intermediary device is arranged between a controller and a plurality of disk devices of {HEAD ~ different performances} arranged in {TAIL ~ a hierarchical manner} 
arranged in
The present invention is storage apparatus where an intermediary device is arranged between a controller and a plurality of disk devices of { HEAD ~ different performances } arranged in { TAIL ~ a hierarchical manner }
OTH 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 REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL