The SCADS director: scaling a distributed storage system under stringent performance requirements
Beth Trushkowsky, Peter Bodík, Armando Fox, Michael J. M. Franklin, Michael I. Jordan, David A. Patterson · 2011
Elasticity of cloud computing environments provides an economic incentive for automatic resource allocation of stateful systems running in the cloud. However, these systems have to meet strict performance Service-Level Objectives (SLOs) expressed using upper percentiles of request latency, such as the 99th. Such latency measure-ments are very noisy, which complicates the design of the dynamic resource allocation. We design and evaluate the SCADS Director, a control framework that reconfig-ures the storage system on-the-fly in response to work-load changes using a performance model of the system. We demonstrate that such a framework can respond to both unexpected data hotspots and diurnal workload pat-terns without violating strict performance SLOs. 1