Optimizing Grid Site Manager Performance with

grid processing, large-scale systems, workload analysis, simulation, performance evaluation, virtual machines, Xen, performance isolation, resource usage optimization Virtualization can enhance the functionality and ease the management of current and future Grids by enabling on-demand creation of services and virtual clusters with customized environments, QoS provisioning and policy-based resource allocation. In this work, we consider the use of virtual machines (VMs) in a data-center environment, where a significant portion of resources from a shared pool are dedicated to Grid job processing. The goal is to improve efficiency while supporting a variety of different workloads. We analyze workload data for the past year from a Tier-2 Resource Center at the RRC Kurchatov Institute (Moscow, Russia). Our analysis reveals that most Grid jobs have low CPU utilization, which suggests that using virtual machines to isolate execution of different Grid jobs on the shared hardware might be beneficial for optimizing the data-center resource usage. Our simulation results show that with only half the original infrastructure employing VMs (50 nodes and four VMs per node) we can support 99 % of the load processed by the original system (100 nodes). Finally, we describe a prototype implementation of a virtual machine management system for Grid computing