However,since EB( extreme binning) utilized the minimum chunk ID of a file as the representative chunk signature,EB was not suitable for backup data stream mainly containing small files. To improve EB,this paper proposed simi index using simi hash as the feature of a file. It was a novel two-level index suitable for workload mainly consisting of small files. Experiment results show that,the deduplication efficiency of simi index is 24. 8% better than EB,and the RAM usage of simiIndex only 0. 265% of that of...