1. A storage management method dividing a physical resource and a logical resource in a storage subsystem, allocating a user per division unit, and performing division management of each of said resources, the storage subsystem having a plurality of channel adapters, a plurality of disk adapters, a shared memory, a cache memory, a physical disk connected to said disk adapters, and a switch for connecting said plurality of channel adapters, said plurality of disk adapters, said shared memory, and said cache memory, the storage management method comprising the steps of: storing, in said shared memory in said storage subsystem, a program-product management table showing presence or absence of a program product providing a management function of each of said resources to the division unit; referring to said program-product management table at the time of executing a management function by said program product in the division unit of said user in accordance with an instruction from said user; and restricting execution of the management function without said program product.