Patent ID: 8086768

Claim:
A storage system, comprising: a first storage subsystem having a first logical volume to be accessed by a host computer; and a second storage subsystem connected to the first storage subsystem and having a second logical volume to be mapped to the first logical volume; wherein the first storage subsystem includes: a memory having definition information for defining a plurality of logical paths that transfer, to the second logical volume, I/O from the host computer to the first logical volume, and a transfer mode of the I/O to the plurality of logical paths; and a controller for controlling the transfer of the I/O based on the definition information, wherein at least two or more logical paths among the plurality of logical paths are defined as active; and wherein if the controller receives the I/O from the host computer, the controller detects an I/O pattern of the I/O, wherein if the detected I/O pattern of the I/O is a sequential access, the controller switches the transfer mode, from a first mode of transferring the I/O to the at least two or more logical paths set as active or a second mode of transferring the I/O to the at least two or more logical paths set as active in round robin, to a third mode of transferring the I/O to a single path among the plurality of logical paths, wherein if the detected I/O pattern of the I/O is a random access, the controller checks whether the second storage subsystem supports the first mode or not switches the transfer mode from the third mode to the first mode in case that the second storage subsystem supports the first mode, and switches the transfer mode from the third mode to the second mode in case that the second storage subsystem does not support the first mode.