Storage apparatus and storage area allocation method

A storage control system, comprising:

• a storage control device being adapted to manage a plurality of storage pool areas each comprising a plurality of logical units and being adapted to manage a plurality of storage areas in each of the plurality of storage pool areas,
• wherein the storage control device is adapted to provide a first virtual logical unit which can be accessed by one of a plurality of host computers and is associated with a first pool area of the plurality of storage pool areas;
• wherein the storage control device is adapted to provide a second virtual logical unit which can be accessed by one of the plurality of host computers and is associated with a second pool area of the plurality of storage pool areas;
• wherein the storage control device is adapted to receive a first write request directed to the first virtual logical unit, and in response to the first write request, allocate, if necessary, one of a plurality of first storage areas in the first pool area of the plurality of storage pool areas to the first virtual logical unit identified by the first write request to be able to store data of the first write request;
• wherein the storage control device is adapted to receive a second write request directed to the second virtual logical unit, and in response to the second write request, allocate, if necessary, one of a plurality of second storage areas in the second pool area of the plurality of storage pool areas to the second virtual logical unit identified by the second write request to be able to store data of the second write request;
• and
• wherein the size of each of the first storage areas is different from that of each of the second storage areas.