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Effectiveness of server load estimation by using requested file size for web server clusters

✍ Scribed by Shinsuke Satake; Hiroshi Inai; Tsuyoshi Arai


Publisher
Wiley (John Wiley & Sons)
Year
2011
Tongue
English
Weight
326 KB
Volume
94
Category
Article
ISSN
1942-9533

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✦ Synopsis


Abstract

Several dynamic load‐balancing methods for web server clusters have been proposed. In order to realize effective load‐balancing, they have required almost real‐time server load information, which could be obtained by observation of client server interactions or by frequent polling from the load‐balancer (dispatcher) to each server. However, observation provides indirect server load information and the polling interval produces a time lag. To overcome that problem, this paper proposes a load‐balancing method based on server load estimation. Under our method, the load‐balancer selects the estimated least‐loaded server, then delivers arriving requests to that server. The estimation is based on the fact that the file transfer delay is proportional to the file size. The fact makes it possible to estimate the load on each server from the last request delivery time and the file size. A performance comparison with the previously proposed methods indicates that our method can achieve an effective load balancing of web server clusters. © 2011 Wiley Periodicals, Inc. Electron Comm Jpn, 94(2): 59–66, 2011; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/ecj.10274