Abstract: I/O bursty is one of the main reasons causing I/O bottleneck, so, it is significant for designing storage system and evaluating system performance to study and accurately synthesize the ubictuitous bursty in I/O workload. Research results show that the traditional poisson assumption is difficult to describe the I/+burstiness behavior well at the longterm time scales,and I/O bursty exhibits the similarity at different time scales,i. e.，self-similarity. So, self-similar models are used to characterize the long-range dependence in I/O workloads. Aimed at the Hurst parameter estimate, this paper summarized the time-domain and frectuency-domain estimators usually used to estimate the degree of self-similarity in storage workloads. After that, some existing models synthesizing I/O workloads were examined, thereinto, the characteristics of self-similar, multi-fractal and alpha-stable models were discussed. After summarizing the unresolved problems, this paper explored the future trend of the study on self-similarity in I/O workloads. The above work will provide a valuable reference for pushing the research on self-similarity in storage workloads.

Key words: Storage system, I/O workload, Self-similarity