Patent ID: 9323463
Filing Date: 2016-04-26
CPC Classification: G06F

Claim Text:
1. A storage system comprising: a first storage apparatus; and a second storage apparatus coupled to the first storage apparatus, each of the first and the second storage apparatuses including: a microprocessor coupled to a host computer; a memory coupled to the microprocessor; and a storage device coupled to the microprocessor, the microprocessor being configured to provide the host computer with a volume based on the storage device, the memory including a shared area and a cache area, the microprocessor of the first storage apparatus being configured to allocate part of the cache area of the first storage apparatus to a virtual cache area, the microprocessor of the second storage apparatus being configured to allocate part of the cache area of the second storage apparatus to the virtual cache area, the shared area being configured to store management information representing data existing in the virtual cache area and a free area size of each of cache areas of the first and the second storage apparatuses, the management information representing association among the data, an apparatus in charge of a cache that is a storage apparatus having a cache area storing the data, an apparatus in charge of a volume that is a storage apparatus having a volume configured to store the data, and a degree of importance representing responsiveness to an input/output (I/O) request from the host computer to the data, the microprocessor of the first storage apparatus being configure to, when a read request to specify first data is received from the host computer, determine whether the first data exists in the virtual cache area based on the management information, when the first data exists in the virtual cache area, determine whether the first data is stored in a first cache area of the first storage apparatus, when the first data is not stored in the first cache area, acquire the first data from a second cache area of the second storage apparatus based on the management information, store the first data in the first cache area, and transmit the first data to the host computer, determine based on the degree of importance whether the first data is to be associated with the first cache area or to be associated with the second cache area, when a determination is made that association with the first cache area is implemented, notify the second storage apparatus to that effect, change an apparatus in charge of a cache of the first data from the second storage apparatus to the first storage apparatus in the management information, and when a determination is made that association with the second cache area is implemented, notify the second storage apparatus to that effect, and delete first data stored in the first cache area.