* Making power management a central theme of data center management
In Nemertes’ New Data Center research, enterprise data center managers identified power consumption and heat dissipation as top challenges.
This trend is driven both by the simple issue of limitations – data centers hitting a wall with respect to the amount of power they can bring in or distribute, or the amount of heat they can control – and by externalities like the rapid rise in energy costs and the prominent occurrence of more frequent brownouts and blackouts in some regions. Data center power load is exceeding capacity in some places, blowing up budgets in others.
So, the enterprise now needs to consider resource consumption more carefully. The two main threads of this concern are in the design phase, with companies designing data centers to handle far more power and cooling; and in the operations phase, with emerging use of active management techniques to minimize power consumption.
Data center design measures are aimed mainly at making sure the power and cooling systems are able to cope with the kinds of densities of current draw and heat throw that are now common and what is foreseeable beyond them. It is, in essence, a one-time, design-time attempt to forestall power and heat problems in the future.
Data center conservation measures are aimed at making sure those limits are not hit, and at saving money along the way if possible. This is an ongoing activity, not something that happens at design time and then only at long intervals during the life of the data center as limits begin to pinch and the unforeseen changes the landscape.
Optimizing for low power consumption in the operating system of a server is a good start, and well established, but this local optimization is not enough. The need for higher-level awareness becomes easily apparent when you look at a mixed workload running across a mass of servers.
It is easy for operating-systems-based power management to keep a particular system running at the lowest current draw possible, but the fact that multiple servers’ workloads can be combined onto a single physical server is not something the OS can see or act on.
Tools like VMware Vmotion make it possible in a virtualized environment to shift the workloads on the fly to expand and contract the number of processors involved in serving a workload, by stacking virtual servers more deeply when CPU loads allow. This works well, but it is a reactive management method.
If power management is to be another central theme in the management of the data center, it needs to be integrated into management software at higher levels, making it a measure of overall system health and performance to be optimized, just as they might currently take job queue length and response times into account.
Integrating power awareness into higher-level management tools means that power management can become proactive as well as reactive. Through active management of the workload, higher-level tools should be able to increase the number of opportunities for reactive optimizations to occur. It can also coordinate workloads to allow for optimization of power consumed by other data center sources such as the network and storage infrastructures. At the highest level, management software can be smart enough to balance loads across data centers – not just to minimize consumption, but also to minimize the cost of that consumption by shifting workloads based on the cost of power in different locations.
Whether it is occurring at the micro level, across the processor cores of a single processor, or at the macro level, across data centers spread across Katrina-scale safe distances, load balancing is no longer only about managing performance. In a very real way, and at several levels, it is also about power, about heat, and about cold hard cash.
Editor’s Note: Does Apple belong in enterprise data centers?: We’re putting together a story to be published in Network World looking at the enterprise-readiness of Apple technology, and we need your help. Have you deployed or evaluated Apple’s XServe servers or its XServe RAID storage platform? What did you find? Do you think Apple’s server and storage gear is ready for enterprise data centers? What are the biggest drivers or deterrents? Should IT administrators become more Mac friendly? We’re looking to tap into our readership and share your experiences with our audience. Please send your ideas and contact information to senior editor Deni Connor.
