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Front. Inform. Technol. Electron. Eng.  2012, Vol. 13 Issue (11): 799-815    DOI: 10.1631/jzus.C1200085
    
Strip-oriented asynchronous prefetching for parallel disk systems
Yang Liu, Jian-zhong Huang, Xiao-dong Shi, Qiang Cao, Chang-sheng Xie
Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China; School of Computer Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
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Abstract  Sequential prefetching schemes are widely employed in storage servers to mask disk latency and improve system throughput. However, existing schemes cannot benefit parallel disk systems as expected due to the fact that they ignore the distinct internal characteristics of the parallel disk system, in particular, data striping. Moreover, their aggressive prefetching pattern suffers from premature evictions and prolonged request latencies. In this paper, we propose a strip-oriented asynchronous prefetching (SoAP) technique, which is dedicated to the parallel disk system. It settles the above-mentioned problems by providing multiple novel features, e.g., enhanced prediction accuracy, adaptive prefetching strength, physical data layout awareness, and timely prefetching. To validate SoAP, we implement a prototype by modifying the software redundant arrays of inexpensive disks (RAID) under Linux. Experimental results demonstrate that SoAP can consistently offer improved average response time and throughput to the parallel disk system under non-random workloads compared with STEP, SP, ASP, and Linux-like SEQPs.

Key wordsParallel disk system      Strip      Sequential prefetching      Asynchronous scheduling     
Received: 29 March 2012      Published: 02 November 2012
CLC:  TP333  
Cite this article:

Yang Liu, Jian-zhong Huang, Xiao-dong Shi, Qiang Cao, Chang-sheng Xie. Strip-oriented asynchronous prefetching for parallel disk systems. Front. Inform. Technol. Electron. Eng., 2012, 13(11): 799-815.

URL:

http://www.zjujournals.com/xueshu/fitee/10.1631/jzus.C1200085     OR     http://www.zjujournals.com/xueshu/fitee/Y2012/V13/I11/799


Strip-oriented asynchronous prefetching for parallel disk systems

Sequential prefetching schemes are widely employed in storage servers to mask disk latency and improve system throughput. However, existing schemes cannot benefit parallel disk systems as expected due to the fact that they ignore the distinct internal characteristics of the parallel disk system, in particular, data striping. Moreover, their aggressive prefetching pattern suffers from premature evictions and prolonged request latencies. In this paper, we propose a strip-oriented asynchronous prefetching (SoAP) technique, which is dedicated to the parallel disk system. It settles the above-mentioned problems by providing multiple novel features, e.g., enhanced prediction accuracy, adaptive prefetching strength, physical data layout awareness, and timely prefetching. To validate SoAP, we implement a prototype by modifying the software redundant arrays of inexpensive disks (RAID) under Linux. Experimental results demonstrate that SoAP can consistently offer improved average response time and throughput to the parallel disk system under non-random workloads compared with STEP, SP, ASP, and Linux-like SEQPs.

关键词: Parallel disk system,  Strip,  Sequential prefetching,  Asynchronous scheduling 
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