Service Availability

Volume 4328 of the series Lecture Notes in Computer Science pp 43-61

Making Services Fault Tolerant

  • Pat Pik Wah ChanAffiliated withDepartment of Computer Science and Engineering, The Chinese University of Hong Kong, Hong Kong
  • , Michael R. LyuAffiliated withDepartment of Computer Science and Engineering, The Chinese University of Hong Kong, Hong Kong
  • , Miroslaw MalekAffiliated withDepartment of Computer Science and Engineering, Humboldt University Berlin

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With ever growing use of Internet, Web services become increasingly popular and their growth rate surpasses even the most optimistic predictions. Services are self-descriptive, self-contained, platform-independent and openly-available components that interact over the network. They are written strictly according to open specifications and/or standards and provide important and often critical functions for many business-to-business systems. Failures causing either service downtime or producing invalid results in such systems may range from a mere inconvenience to significant monetary penalties or even loss of human lives. In applications where sensing and control of machines and other devices take place via services, making the services highly dependable is one of main critical goals. Currently, there is no experimental investigation to evaluate the reliability and availability of Web services systems. In this paper, we identify parameters impacting the Web services dependability, describe the methods of dependability enhancement by redundancy in space and redundancy in time and perform a series of experiments to evaluate the availability of Web services. To increase the availability of the Web service, we use several replication schemes and compare them with a single service. The Web services are coordinated by a replication manager. The replication algorithm and the detailed system configuration are described in this paper.


Web service availability redundancy reliability