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Load balancing algorithm using tape migration mechanisms for scalable tape archiver and its performance evaluation

✍ Scribed by Toshihiro Nemoto; Masaru Kitsuregawa


Publisher
John Wiley and Sons
Year
2000
Tongue
English
Weight
421 KB
Volume
31
Category
Article
ISSN
0882-1666

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✦ Synopsis


In this paper the authors describe a load balancing algorithm and its validity in a scalable tape archiver consisting of a small-scale tape archiver used as a single element and a tape migration device connected to these elements which enables the physical transfer of tapes. With the rapid development of small-scale archivers for multimedia applications in recent years, such archivers are expected to become commercial products in the near future. By connecting an arbitrary number of such inexpensive element archivers together, an archiver system of the desired scale can be created in a flexible and cost-efficient fashion. In this paper the authors describe their load balancing algorithm for use among the element archivers and then demonstrate its validity through simulations. By balancing any biases in the access frequency through the use of the tape migration mechanism, the authors show that considerable performance improvements can be obtained. In addition, they also show that the tape migration mechanism is useful for tape drive failures, as well as demonstrating that performance improvements can be obtained even when using file striping. Finally, the authors perform simulations using the access history for a satellite image database and show that the tape migration mechanism is useful for realworld applications as well.