Evaluation of expanded heuristics in a heterogeneous distributed data staging network

Abstract

Providing up-to-date input to users' applications is an important data management problem for a heterogeneous distributed computing environment, where each data storage location and intermediate node may have different data available, storage limitations, and communication links available. Sites in the heterogeneous network request data items and each request has an associated deadline and priority. In a military situation, the data staging problem involves positioning data for facilitating a faster access time when it is needed by programs that will aid in decision making. This work concentrates on solving a basic version of the data staging problem in which all parameter values for the communication system and the data request information represent the best known information collected so far and stay fixed throughout the scheduling process. The heterogeneous network is assumed to be oversubscribed and not all requests for data items can be satisfied. Three multiplesource shortest-path algorithm based procedures for finding a near-optimal schedule of the communication steps for staging the data are described. Each procedure can be used with each of three cost criteria developed here (based on results from earlier experiments). A subset of the possible procedure/cost criterion combinations are evaluated in simulation studies considering different priority weighting schemes, different average number of links used to satisfy each data request, and different network loadings. The proposed heuristics are shown to perform well with respect to upper and lower bounds.

Heuristics for Scheduling Data Requests Using Collective Communications in a Distributed Communication Network

“…Because these performed well, and the problem studied in this paper is similar to that researched in [17,19], two terms are defined and combined in a manner that is equivalent to those weighted priority and urgency terms. In addition, two other terms, bw ratio and trans hour, are created to reflect the differences between the systems.…”

“…The AICE is similar to the environment for the BADD (Battlefield Awareness and Data Dissemination) project [17,19]. An intuitive description of the usefulness of AICE is as follows.…”

“…The measure used in this research to determine the performance of a schedule is based on a weighted priority term, also used in [17,19] , where | was set to 4 and 16 for this research (changing the particular scheme used for weighting the priorities, andÂor changing the exact values used, would not change the rest of the system).…”

“…The study in [17,19] utilized an urgency term and a weighted priority term in the cost criteria. Because these performed well, and the problem studied in this paper is similar to that researched in [17,19], two terms are defined and combined in a manner that is equivalent to those weighted priority and urgency terms.…”

Towards an Agent Framework for Grid Computing

“…Grid environments need to assure that the resources are available to the component applications locally even if the nodes are distributed geographically, an operation usually referred to as data staging [8,9,10]. The data staging operation for Bond grid framework is quite similar to application execution.…”