Patent ID: 8634156

Claim:
A storage system comprising: a magnetic disk apparatus including a plurality of magnetic disk drives; and a control apparatus which controls an access to a magnetic disk drive in the magnetic disk apparatus, wherein: the magnetic disk apparatus has a first spin up controller which spins up a spun down magnetic disk drive in the magnetic disk apparatus; and the control apparatus has: a second spin up controller which spins up a spun down magnetic disk drive in the magnetic disk apparatus; and a separate controller which does not permit the magnetic disk apparatus to be used and prevents the second spin up controller from spinning up the spun down magnetic disk drive in the magnetic disk apparatus when the number of the spun down magnetic disk drives in the magnetic disk apparatus reaches a predetermined threshold, and permits the magnetic disk apparatus to be used and permits the second spin UP controller to spin UP the spun down magnetic disk drive in the magnetic disk apparatus after a predetermined period of time.