Abstract: After the coming of Big Data Time,the demands for cloud storage are becoming stronger．Performance evaluation of cloud storage is always the key and difficult point of research of cloud storage system．Through analyzing the data access process of typical cloud storage platforms,the data access model of cloud storage was built．With the help of iptools capturing IP packages,the time cost of each phase of processing users’ access was gained．The true performance can be observed when ignoring the network interference．The test results show that the model is scientific and the test method can gain the true performance of cloud storage system effectively.

Key words: Cloud storage,Performance evaluation,Evaluation metrics