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Modeling and Improving Security of a Local Disk System for Write-Intensive Workloads


             Mais Nijim    Xiao Qin*                                            Tao Xie

      Department of Computer Science                       Department of Computer Science                        

New Mexico Institute of Mining and Technology          San Diego State University                   

            Socorro , New Mexico 87801                          San Diego , California 92182                                 

              {mais, xqin}@cs.nmt.edu                                    xie@cs.sdsu.edu     

Since security is of critical importance for modern storage systems, it is imperative to protect stored data from being tampered or disclosed. Although an increasing number of secure storage systems have been developed, there is no way to dynamically choose security services to meet disk requests’ flexible security requirements. Furthermore, existing security techniques for disk systems are not suitable to guarantee desired response times of disk requests. We remedy this situation by proposing an adaptive strategy (referred to as AWARDS) that can judiciously select the most appropriate security service for each write request while endeavoring to guarantee the desired response times of all disk requests. To prove the efficiency of the proposed approach, we build an analytical model to measure the probability that a disk request is completed before its desired response time. The model also can be used to derive the expected value of disk requests’ security levels. Empirical results based on synthetic workloads as well as real I/O-intensive applications show that AWARDS significantly improves overall performance over an existing scheme by up to 358.9% (with an average of 213.4%).

* Corresponding author.  http://www.cs.nmt.edu/~xqin  A version of this paper appeared in the ACM Transactions on Storage, vol. 2, no. 4, pp. 400-423, Nov. 2006.