Survivability-oriented self-tuning of web systems

Running in a highly uncertain and changing environment, Web systems cannot always provide full set of services with optimal quality, especially when the workload is high or failures in sub-systems occur frequently. It is thus desirable to continuously maintain a high satisfaction level of the system value proposition, hereafter survivability assurance, while relaxing/sacrificing certain quality/functional requirements that are not crucial to the survival of the Web systems. In this paper, we propose a requirements-driven self-tuning method for survivability assurance of Web systems. Using a value-based feedback controller plus a requirements-oriented reasoner, our method makes both quality and functional requirements tradeoffs decisions at runtime