Abstract:Network storage methods (e.g. FC-SAN) with virtual storage technology are becoming a powerful substitution of DAS in digital libraries and other massive storage applications. However the efficiency of FC-SAN virtual storage strongly depends on some attributes of the stored documents. In some cases, FC-SAN may even perform no better than the sharing data on LAN. This paper illustrates this point by a study on the data placement and access path selection issues in a network storage environment. The paper first presents a linear timeconsuming model of data access through the analysis of the virtual storage principle and then gives a decision-making method for data placement and access path selection problem. In the development of this method, the concept of equivalent of virtual storage cost is defined to evaluate the data placement cost in the FC-SAN virtual storage environment. Finally, the theoretical analysis, methods, and assumptions are proved by the experimental results based on a massive storage subsystem in a digital library prototype.