On Elasticity Measurement in Cloud Computing

Elasticity is the foundation of cloud performance and can be considered as a great advantage and a key beneNt of cloud computing. However, there is no clear, concise, and formal deNnition of elasticity measurement, and thus no ePective approach to elasticity quantiNcation has been developed so far. Existing work on elasticity lack of solid and technical way of deNning elasticity measurement and deNnitions of elasticity metrics have not been accurate enough to capture the essence of elasticity measurement. In this paper, we present a new deNnition of elasticity measurement and propose a quantifying and measuring method using a continuous-timeMarkov chain (CTMC) model, which is easy to use for precise calculation of elasticity value of a cloud computing platform. Our numerical results demonstrate the basic parameters aPecting elasticity as measured by the proposed measurement approach. Furthermore, our simulation and experimental results validate that the proposed measurement approach is not only correct but also robust and is ePective in computing and comparing the elasticity of cloud platforms. Our research in this paper makes signiNcant contribution to quantitative measurement of elasticity in cloud computing.