Storage controller and storage control program

PROBLEM TO BE SOLVED: To provide a storage controller capable of performing copying relevant to a copy instruction which is under processing when a failover occurs on a newly activated storage unit 3 using a correct LUN.SOLUTION: When a failover is generated, a determination section 32a determines whether or not the own unit is the master. When the determination section 32a determines that the own unit is not the master, a conversion section 32b converts virtual LUNs of a copy source and a copy destination to actual LUNs. A copy section 32c performs a copy processing by using the actual LUNs converted by the conversion section 32b.SELECTED DRAWING: Figure 9