Noshir Cavas Wadia

Dynamic Surge Protection: An Approach to Handling Unexpected Workload Surges with Resource Actions that Have Lead Times

Today’s information technology departments have significantly varying demands for resources due to unexpected surges in subscriber demands (e.g., a large response to a product promotion). Further complicating matters is that many resource actions done in response to surges (e.g., provisioning or de-provisioning an application server) have substantial delays (lead times) between initiating the resource action and its taking effect. This paper describes dynamic surge protection, an approach to handling unexpected workload surges in systems that have lead times for resource actions. Dynamic surge protection incorporates three technologies: adaptive short-term forecasting, on-line capacity planning, and configuration management. The paper includes empirical results from evaluations done on a research testbed, including favorable comparisons with a threshold-based heuristic. The results from an extended test also show that service objectives can be maintained cost-effectively.

Capacity planning tools for web and grid environments

A key aspect in managing resources for customer sites is to predict and assess the load associated with a site in order to figure out how best to allocate resources for the site over time and to efficiently schedule tasks. The cost associated with the site and return on investment are also key parameters. This paper describes work we have done in developing tools for answering these critical questions. The tools use both analytical models and discrete event simulations to predict performance and analyze costs needed for handling a customer workload while satisfying the service level objectives. These tools provide capacity and load planning, performance simulation, and cost and financial analyses. Our tools have been used successfully by several major customers, and those experiences have shaped how the tools have evolved over time.