In a distributed storage system, client terminals make access to virtual storage areas provided as logical segments of a storage volume. Those logical segments are associated with physical segments that serve as real data storage areas. A management data storage unit stores management data describing the association between such logical segments and physical segments. Upon receipt of access requests directed to a specific access range, a segment identification unit consults the management data to identify logical segments in the specified access range and their associated physical segments. A remapping unit subdivides the identified logical segments and physical segments into logical sub-segments and physical sub-segments, respectively, and remaps the logical sub-segments to the physical sub-segments according to a predetermined remapping algorithm. A data access unit executes the access requests based on the remapped logical sub-segments and physical sub-segments.