Addressing power and thermal challenges in the datacenter

Computer Technology Review, Nov, 2004 by Charles Rego, Dave Wagner

Rising utility rates and escalating computing requirements are creating new power and thermal challenges for datacenter managers. Today's high-density rack and blade servers bring these issues into especially sharp focus. Since these architectures are inherently more scalable, adaptable, and manageable than traditional platforms, they deliver much needed relief in complex, crowded datacenters. Yet they also introduce power and thermal loads that are substantially higher than those of more currently deployed systems. In some cases, they may even push the cooling infrastructures of older design facilities beyond their limits.

A long-term solution to these challenges will require broad industry innovation and collaboration. The most important enhancement is a shift toward multi-core architectures that incorporate two or more processing units on a single chip. This would deliver major performance improvements while helping maintain power usage.

Moving Toward Integrated Datacenter Management: Performance Planning

The goal of datacenter integration is to enable IT facilities managers to automate and optimize performance, power and cooling management across the datacenter, and to monitor and control all relevant variables at the component, system, rack and datacenter level. In the short term, companies can move towards this environment through an integrated datacenter approach. The goal of this integrated approach is to ensure that IT planning factors their performance (or capacity) requirements to sustain appropriate business service levels with the implications of underlying IT resource decisions beyond simple "price/performance" ratios. Today, ISVs provide performance and prediction software that enables companies to plan for the balancing of workloads, response times and system resource utilization with business and IT HW resource changes. Those plans can then be factored into power and thermal planning activities, which fall out from resource technology decisions and timelines. The components of such a performance/capacity plan include:

Build an Asset Inventory: It's impossible to plan datacenter requirements without understanding your starting point. You must be able to answer the "What" question about your resources. Know and document the physical aspects of your asset inventory including software licenses, asset purchase dates, cost, owner, server/desktop identity, etc., in order to better understand the performance utilization of underlying assets.

Baseline Asset Performance: After the physical assets have been catalogued, it is important to answer the "How" question in terms of asset performance utilization. It is not uncommon to find server CPU utilization on some applications averaging well below 15% across the typical enterprise. Leveraging performance software tools enables businesses to effectively collect, analyze and present performance data that directly associates performance measurements with business-oriented metrics. This first step also typically helps identify "low hanging fruit" opportunities. For example, idle resources, which can potentially be rapidly re-provisioned in lieu of incremental resource acquisition.

Report/View: Once performance utilization information is available, it is time to understand the "Why" aspect. Should IT care about any given resource? Reporting capabilities enable IT professionals to examine the correlation between performance/utilization against asset ownership and purpose. It helps companies understand not just that a given asset might be "underutilized" but that it has an (un)important role within the organization. By correlating utilization, business purpose and stakeholder information, IT can make rapid, informed decisions to proceed to more comprehensive asset performance analysis for those assets whose performance (or cost) factors necessitate more detailed planning.

Asset Analysis: It is critical to understand the impact of the business cycle on the utilization of underlying IT resources. No business plan (whether for performance/capacity or for technology choice, power and/or cooling) is complete without factoring the requirements to sustain business service-level requirements across the business cycle. Optimizing asset utilization in conjunction with reductions in power and cooling costs is worthless if the resultant configurations under (or over) provision the needs of the business. Factors such as business workload performance over time (e.g., "trade settlement application requires X CPU and Y I/O resources for a given transaction rate"), business cycle variance (e.g., "trade settlement transactions peak at 5 p.m. daily, with monthly variance of Y, and business peaks quarterly") can ensure the all-important common view between IT and business so needed to build an overall datacenter resource plan.

Asset Modeling: Data center planning requires the analysis of various technology choices in terms of impact on business throughput, response time and utilization. The previous steps provide the foundation upon which business change scenarios (growth, consolidation, etc.) can be factored into the overall performance analysis, ensuring high-confidence that the results will not only resolve today's performance problems, but will cost-effectively scale with a company's business. This results in a series of technology choices, which can then be evaluated as part of the Power and Thermal Planning effort.