Patent ID: 7908449
Filing Date: 2011-03-15
Classification: G06F

Abstract:
1. A storage system coupled to a host computer through a network, the storage system comprising: a first interface adapter coupled to a host computer through the network; a plurality of first disk devices including a first volume; a first control unit coupled to the first interface adapter and the first disk devices, the first control unit including a first processor and a first switch; a second interface adapter coupled to the host computer through the network; a plurality of second disk devices including a second volume; a second control unit coupled to the second interface adapter, the second control unit including a second processor and a second switch and a memory storing data sent from the host computer to the second volume temporarily; and a connection line connected to the first switch of the first control unit and the second switch of the second control unit, wherein the first control unit controls Input/Output (I/O) requests to the first volume, and the second control unit controls I/O requests to the second volume, wherein when data stored in the first volume is copied to the second volume, the first control unit reads data stored in the first volume, and sends a write request regarding the data stored in the first volume to the second storage system through the first switch, the connection line and the second switch, the second control unit secures a region for data of the write request in the memory of the second control unit, and the first control unit transfers the data of the write request through the first switch, the connection line and the second switch to the secured region in the memory of the second control unit, and the second control unit writes the data stored in the memory in the second volume, wherein, if the first control unit receives a write request from the host computer while data copy is performed from the first volume to the second volume through the first switch, then the connection line and the second switch, the first control unit determines whether a target area of the write request is copied or not, wherein, if the target area of the write request has been already copied, then the first control unit sends the write request to the second control unit through the first switch, the connection line and the second switch, and the first and second control units respectively write data of the write request to the first and second volumes, and wherein, if the target area of the write request has not been copied yet, then the data of the write request is written to the first volume.