Patent ID: 8176248

Claim:
A control device comprising: a plurality of first interfaces being coupled to a host computer; a plurality of second interfaces being coupled to a plurality of storage systems, each of which comprising a plurality of storage devices and a storage controller providing at least one logical unit, using the plurality of storage devices, to the control device, wherein a plurality of logical units, which are provided by a plurality of storage controllers of the plurality of storage systems, include a first logical unit and a second logical unit; and a controller managing the plurality of logical units provided by the plurality of storage controllers of the plurality of storage systems and providing a third logical unit to the host computer, the third logical unit including a first storage area and a second storage area, wherein data sent to the first storage area in the third logical unit is to be stored in a storage area in the first logical unit, and data sent to the second storage area in the third logical unit is to be stored in a storage area in the second logical unit.