Patent ID: 8041890

Claim:
A method for accessing a target disk, wherein a Peripheral Component Interconnect Express, PCIe, switching unit is provided between a processing unit and a control unit of a master disk array, a PCIe switching unit and a control unit are provided in a slave disk array, and the disk arrays are connected to each other via their respective PCIe switching units, the method further comprises: in each of the disk arrays, mapping addresses of all the disks in the disk array to an address space and storing the address space at a first port of the PCIe switching unit in the disk array via which the PCIe switching unit is connected directly to the control unit in the disk array, and mapping addresses of disks in all subsequently cascaded slave disk arrays to another address space and storing the another address space at a second port of the PCIe switching unit in the disk array via which the PCIe switching unit is connected to a PCIe switching unit on the next stage; obtaining, by the processing unit of the master disk array, a command or data, and sending, by the processing unit, the obtained command or data to the PCIe switching unit of the master disk array; sending, by the PCIe switching unit of the master disk array, the command or data to a control unit in a corresponding disk array according to an address of the target disk indicated in the received command or data comprising: sending, by the PCIe switching unit of the master disk array, the received command or data to its first port and second port; and determining, respectively by the first and second ports of the PCIe switching unit of the master disk array, whether the address of the target disk indicated in the received command or data is in the range of address space stored at their respective first and second ports; if the address is in the range of the address space, sending the received command or data directly to the control unit in a corresponding disk array, otherwise not forwarding the received command or data; and sending, by the control unit in the corresponding disk array, the received command or data to the target disk that is directly connected to the control unit in the corresponding disk array.