A plurality of storages having respective attributes and a method for
preserving data is provided in consideration of the attribute (performance
or cost) and the operation ratio of the storage and the using frequency of
the data in the storage area network. The information processing system of
the invention includes a location management unit for managing a location
of the data stored in the storage, an information duplication unit for
duplicating the data between the storages, and an attribute preservation
unit for preserving information for representing the attribute of each
storage. The location management unit duplicates and moves the data
between the storages by using the information duplication unit, based on
the operation ratio of the storage, the access frequency of the data, the
control information and the billing information.
