Stochastic Model for QoS Assessment in Multi-tier Web Services


Service Level Agreements (SLAs) are used to guarantee quality of service (QoS) between customers and service providers. In an SLA, parties establish a common set of rules and responsibilities. In this paper we propose a practical stochastic modeling of a multi-tier architecture considering SLAs for specific transactions. The model is parameterized with available performance testing data for a real web service, and with a testing environment having unpredictable and unknown external workloads of simultaneous execution. In addition, we present multiple scenarios of external applications impacting on the SLAs in our target architecture. Having a previous knowledge about the average time demanded by some external applications, our model results can provide evidences when the system under test will not respect the agreed-upon SLAs. Finally, we discuss possible model extensions towards further unknown workload characterizations and considerations about application execution profiling.

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Additional Information: © 2011 Elsevier B.V. Open access under CC BY-NC-ND license.
Publication ISSN: 1571-0661
Last Modified: 21 Feb 2024 08:11
Date Deposited: 07 Jan 2022 13:35
Full Text Link: http://www.scop ... tnerID=MN8TOARS
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PURE Output Type: Article
Published Date: 2011-09-27
Authors: Czekster, R.M. (ORCID Profile 0000-0002-6636-4398)
Fernandes, P.
Sales, A.
Webber, T.
Zorzo, A.F.

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