Information system and data transfer method of information system

A method in a storage system including a first storage device including a plurality of physical storage devices and a controller, and a second storage device including a plurality of physical storage devices and a controller, said method comprising the steps of:

• configuring, by the controller of the first storage device, a first logical volume on the physical storage devices of the first storage device;
• configuring, by the controller of the second storage device, a second logical volume on the physical storage devices of the second storage devices;
• providing, by the controller, a first virtual volume, which corresponds to the first logical volume;
• providing, by the controller, a second virtual volume, which corresponds to the second logical volume;
• storing data in the first logical volume and duplicating the data stored in the first logical volume to the second logical volume;
• and
• accessing, by the computer, the data stored in the first logical volume via the first virtual volume and the data stored in the second logical volume via the second virtual volume using the same identification number.