Storage system and method for data transfer between storage systems

摘要

There is realized a storage system which can reduce the limitation of a device number used by a host CPU at the time of duplexing data. A micro processor of a source external storage controller unit unifies a plurality of write data received from the host CPU to the same data bus to provide one unit of data transmitting to a target storage system. A number not dependent on the device number used when the host CPU specifies a device is allocated to this. Then, the source external storage controller unit sends the write data to the target external storage controller unit. This can receive/send the data without depending on the target specifying device number.