Cloud storage is one of the services provide in cloud computing which has been increasing in reputation. With the growing data size of cloud computing, a decrease in data volumes could help provider reducing the costs of running large storage system and saving energy use. So data de-duplication techniques have been brought to recover storage competence in cloud storages. In this paper, we suggest a dynamic de-duplication system for cloud storage, which aim to advance storage competence and maintain redundancy for fault acceptance.