Integrated deduplication systems, data storage devices, and the server device

First, a duplicate elimination process based on a first duplicate elimination process, in which both a duplicate elimination effect and a processing load are low, is executed. Information related to a processing result of the duplicate elimination process based on the first duplicate elimination process is acquired prior to execution of a second duplicate elimination process, in which both the duplicate elimination effect and the processing load are high. Target data of the second duplicate elimination process is narrowed down based on the acquired information. The second duplicate elimination process is applied only to the narrowed down target data. As a result, an integrated duplicate elimination system with a lower processing load than in a conventional system is realized while attaining a high duplicate elimination effect.