An integrated approach to resource pool management: Policies, efficiency and quality metrics

The consolidation of multiple servers and their workloads aims to minimize the number of servers needed thereby enabling the efficient use of server and power resources. At the same time, applications participating in consolidation scenarios often have specific quality of service requirements that need to be supported. To evaluate which workloads can be consolidated to which servers we employ a trace-based approach that determines a near optimal workload placement that provides specific qualities of service. However, the chosen workload placement is based on past demands that may not perfectly predict future demands. To further improve efficiency and application quality of service we apply the trace-based technique repeatedly, as a workload placement controller. We integrate the workload placement controller with a reactive controller that observes current behavior to i) migrate workloads off of overloaded servers and ii) free and shut down lightly-loaded servers. To evaluate the effectiveness of the approach, we developed a new host load emulation environment that simulates different management policies in a time effective manner. A case study involving three months of data for 138 SAP applications compares our integrated controller approach with the use of each controller separately. The study considers trade-offs between i) required capacity and power usage, ii) resource access quality of service for CPU and memory resources, and iii) the number of migrations. We consider two typical enterprise environments: blade and server based resource pool infrastructures. The results show that the integrated controller approach outperforms the use of either controller separately for the enterprise application workloads in our study. We show the influence of the blade and server pool infrastructures on the effectiveness of the management policies.