%0 Journal Article
%T Reliability Evaluation of Service-Oriented Architecture Systems Considering Fault-Tolerance Designs
%A Kuan-Li Peng
%A Chin-Yu Huang
%J Journal of Applied Mathematics
%D 2014
%I Hindawi Publishing Corporation
%R 10.1155/2014/160608
%X Service-oriented architecture (SOA) provides an elastic and automatic way to discover, publish, and compose individual services. SOA enables faster integration of existing software components from different parties, makes fault tolerance (FT) feasible, and is also one of the fundamentals of cloud computing. However, the unpredictable nature of SOA systems introduces new challenges for reliability evaluation, while reliability and dependability have become the basic requirements of enterprise systems. This paper proposes an SOA system reliability model which incorporates three common fault-tolerance strategies. Sensitivity analysis of SOA at both coarse and fine grain levels is also studied, which can be used to efficiently identify the critical parts within the system. Two SOA system scenarios based on real industrial practices are studied. Experimental results show that the proposed SOA model can be used to accurately depict the behavior of SOA systems. Additionally, a sensitivity analysis that quantizes the effects of system structure as well as fault tolerance on the overall reliability is also studied. On the whole, the proposed reliability modeling and analysis framework may help the SOA system service provider to evaluate the overall system reliability effectively and also make smarter improvement plans by focusing resources on enhancing reliability-sensitive parts within the system. 1. Introduction Service-oriented architecture (SOA) has become a major distributed computing framework [1]. With characteristics like standardized interfaces, loosely coupled structure, cross-platform as well as elastic service discovery, deployment, and reuse capabilities, SOA opens a new door to faster integration of existing software components from different parties, especially in the scheme of Web services (WS). Legacy components may still live within the system via service adapters [2], which is good for enterprises which prefer system upgrades in gentle and stable way. It is noted that SOA also makes fault-tolerance (FT) techniques feasible for building reliable systems. Since it is difficult to build failure-free useful systems under limited development costs and the pressure of time to market, software fault tolerance [3], whose concepts originated from hardware reliability assurance, was proposed as an effective way to utilize redundancy to mask software failures and recover to normal operational states in a long running system. However, the extra costs of bringing out alternative software designs (redundancy) basically limit the applications of software
%U http://www.hindawi.com/journals/jam/2014/160608/