The rapid development of the Internet, fast drop of storage cost, and the great improvement of storage capacity have created an environment with an enormous amount of digital data. In addition to the traditional goals like performance, scalability, availability, and reliability, other challenges including manageability, searching for the desired information, energy efficiency, long-term data preservation, and data security become increasingly important for storage systems. We first present the evolution path of the past development of storage systems. The impact of the advancement of disk technology on fault tolerance is discussed next. The potential solutions and research issues of the new challenges are also briefly discussed.