Patent ID: 8074090

Claim:
A storage system, comprising: one or more host systems; a plurality of storage apparatuses in which each storage apparatus comprises a plurality of storage devices and is operable to use said storage device to provide said one or more host systems with a storage extent accessible by said one or more host systems; and a management apparatus operable to manage said storage apparatuses, wherein said management apparatus includes information concerning the access schedule where said host system accessed said storage extent, and, based on said schedule information, said management apparatus is further operable to migrate to a second storage apparatus a storage extent of a first storage apparatus having said storage extent to be accessed by said host system, create a period in which said first storage apparatus does not have said storage extent to be accessed by said host system, and turn off a main power supply of said first storage apparatus during said period, wherein said schedule information comprises information concerning the schedule for operating one or more businesses provided by said host system to a user and information defining the access destination storage extent of data required by said host system to execute said businesses, and wherein a migration destination in said second storage apparatus is selected from among said plurality of storage apparatuses with the power supply turned on.