Software rejuvenation is modeled in a clientserver system, which provides resources to priority classes of users. To assure availability, resource reservation policies are adopted for the higher priority classes. In a...
详细信息
Software rejuvenation is modeled in a clientserver system, which provides resources to priority classes of users. To assure availability, resource reservation policies are adopted for the higher priority classes. In addition software rejuvenation is proposed to optimize resource availability. The system is modeled by a cyclic nonhomogeneous Markov chain to capture the variation of the arrival and service rates during a day period. An optimization problem is solved based on a similar previous work and given the optimal resource reservation policy obtained by its solution, rejuvenation is performed and the optimal rejuvenation policy is determined. As a measure of resource availability the blocking probability of each priority class is used. Performability indicators expressing the total cost are also derived, with respect to the optimal resource reservation and optimal rejuvenation policies, to examine whether rejuvenation benefits the system in terms of cost. To derive the blocking probabilities, the limiting probability distribution is computed using explicit generalized approximateinverse preconditioning for solving efficiently sparse linear systems of algebraic equations. Copyright (c) 2012 John Wiley & Sons, Ltd.
Resource availability optimization is studied oil a server-client system where different users are partitioned into priority classes. The aim is to provide higher resource availability according to the priority of eac...
详细信息
Resource availability optimization is studied oil a server-client system where different users are partitioned into priority classes. The aim is to provide higher resource availability according to the priority of each class. For this purpose, resource reservation is modeled by a homogeneous continuous time Markov chain (CTMC), but also by a cyclic non-homogeneous Markov chain (CNHMC) as there is a cyclic behavior of the users' requests for resources. The contribution of the work presented consists in the formulation of a multiobjective optimization problem for both the above cases that aims to determine the optimal resource reservation policy providing higher levels Of resource availability for all classes. The optimization problem is solved either with known methods or with a proposed kind of heuristic algorithm. Finally, explicit generalized approximateinverse preconditioning methods are adopted for solving efficiently sparse linear systems that are derived, in order to compute resource availability. (C) 2008 Elsevier B.V. All rights reserved.
. The need for a more accurate modeling of the performance of systems whose functioning mainly dependant on external time parameters such as the number of requests during a particular time phase, led us to a novel app...
详细信息
暂无评论