Storage system and method of controlling storage system

A control method in a storage system for storing data requested by a host computer to be written, the storage system including:

• a host interface coupled to the host computer;
• a storage device for storing the data requested by the host computer to be written;
• a disk interface connected to the storage device;
• at least one processor for processing the data requested to be written;
• a cache memory for storing the data requested by the host computer to be written;
• and
• a cache controller for controlling data inputs to and outputs from the cache memory, the cache memory including a first memory which can be accessed by way of either access that can specify an access range by a line or access that continuously performs a read and a write, the cache controller including a second memory which has a higher flexibility than the first memory in specifying an access range, the control method including the steps of:
• determining, by an access destination determination unit of the cache controller, an address of an access destination upon reception of a request for access to the cache memory from the at least one processor;
• holding, by the access destination determination unit, access destination information which associates a storage area of the second memory with an address space of the first memory;
• switching, by the cache controller, a request for an access to a specific address into an access to a corresponding address in the second memory;
• backing UP, by the at least one processor, data held in the second memory to the first memory;
• stopping, by the at least one processor, a function of the access determination unit;
• changing, by the at least one processor, a configuration of a device installed in the storage device or detecting a change in the configuration of the device installed in the storage system;
• determining, by the at least one processor, a place to store control information related to the device based on configuration information after the change of the configuration of the device;
• setting, by the at least one processor, the determined place to store the control information to the access destination information;
• migrating, by the at least one processor, at least part of the control information held in the first memory to the second memory in accordance with the determined place to store the control information;
• and
• resuming, by the at least one processor, the function of the access destination determination unit after the migration.