Design and experimental evaluation of an adaptive object replication algorithm in distributed network systems

In this paper, we propose an adaptive object replication algorithm suitable for distributed network systems and carry out implementations to quantify its performance. We first present a theoretical framework by using a mathematical cost model that considers all the costs associated with servicing a request, i.e., I/O cost, control-message transferring cost, and data-message transferring cost. Using this cost model, we develop an efficient and auto-adaptive object replication algorithm, referred to as Adaptive Distributed Request Window (ADRW) algorithm. Our objective is to dynamically adjust the allocation schemes of objects based on the decision of ADRW algorithm, i.e., whether the system is read-intensive or write-intensive, so as to minimize the total servicing cost of the arriving requests. Our experimental results convincingly demonstrate that the proposed algorithm is adaptive and is superior to several related algorithms in the literature in terms of the average cost of servicing a request.