1. An storage system coupled to a server for managing object-based data comprising: a processor; a memory; and a plurality of storage devices, wherein in deduplicating data, said storage system obtains information of boundary location of objects included in the data subject to deduplication, divides the data subject to deduplication based on said information of boundary location of the objects, and calculates hash value of said divided data, wherein said storage system provides a plurality of virtual volumes to said server, and each page of said plurality of virtual volumes are allocated from a plurality of logical volumes allocated from said plurality of storage devices, said allocation of each said page from said plurality of logical volumes is performed when the page is subject to a write command, wherein said memory maintains said information of the boundary location of objects and allocation between the pages of said plurality of virtual volumes and said plurality of logical volumes, wherein said server includes an application program which reads data from said plurality of virtual volumes, processes said data, and writes the data to said plurality of virtual volumes, wherein said information of boundary location of objects are managed by said application program, said information of boundary location of objects including an address of said virtual volume, and wherein said information of boundary location of objects are obtained from said server.