The mainframe’s advantages in terms of power and cooling costs are well-documented. Frank Bereznay, capacity manager, Kaiser Permanente, for example, found that his company’s mainframe was its lowest power user, by a large percentage, when compared to the network, servers and storage (see “Forecasting Data Center Power Requirements: Tips From the Trenches,” regions.cmg.org/regions/nccmg, August 2008). His experience reflects that of many other owners of large data centers.
IBM also has created a Mainframe Gas Gauge for the System z9 that provides statistics for KW, BTU/hour, and inlet temperature displayed in real-time. IBM has observed that the power differential between idle and fully loaded for a mainframe is quite small—under 150 watts (see “Mainframe Gas Gauge—Frequently Asked Questions,” ftp://ftp.software.ibm.com/systems/z/pdf/Mainframe_Gas_Gauge_FAQ.pdf, October 2007). In assessing other environmental factors (i.e., floor space, cooling, etc.), a server farm of 1,000 or more servers can easily fit into a small z9 partition running Linux under z/VM. This is a positive step for all environmental factors and will reduce overall power consumption.
ITIL capacity management can now realistically include power consumption and other environmental considerations, as well as classic IT capacity metrics such as CPU workloads and network bandwidth. It even might be reasonable to assert that any capacity planning document created today should include a section on energy consumption and environmental impact.
People are another aspect of ITIL capacity management. Again, the people component has historically been thought of in terms of available headcount and salary budget constraints. But people also use energy to travel to work. They use energy when they’re in their workspaces. So, part of being “green” is factoring people into the environmental equation.
Here, too, the mainframe delivers differentiated performance. The support and overhead costs of mainframes tend to be much less than for server farms. Arcati suggests that the cost differential could be as much as three times higher for UNIX support and six times higher for Windows support (see “The Dinosaur Myth,” www.arcati.com/dinomyth.htm, 2004). Arcati’s cost calculations include only the salaries, not the associated energy and floor space costs, so the actual differential is probably quite a bit higher.
The argument becomes even more compelling when considering real-world examples of data centers where thousands of servers have been eliminated by having their workloads migrated to System z under Linux. One such example is IBM’s own data center, where 3,900 servers were migrated to mainframes (see “Mainframes Color IBM Data Centers Green,” www.ibm.com/news/us/en/2007/08/01/v345523z96582s28.html, August 2007). Support costs were dramatically reduced, as were power and floor space costs.
ITIL demand management principles also can be applied by negotiating agreements with power providers to lower their costs during off-peak hours. These discounts can then be factored into chargeback structures to further support the shifting of workloads to times that make the most economic sense.
ITIL availability management ensures resources are available when they’re needed. This doesn’t, however, mean that the resources required for peak periods need to be made continuously available. A “greener” approach is to use functionality such as Capacity Upgrade on Demand (CUoD), on/off capacity on demand, and backup capacity. These tools bring online processors and memory online only as needed to ensure that IT organizations aren’t paying for capacity they don’t need—and that they also aren’t using power they don’t need to keep that capacity running.
Disaster Recovery (DR) configurations for mainframes typically rely on failover to Logical Partitions (LPARs) and systems that are already in use. This further increases the green value of the mainframe, since there’s no requirement to maintain idle servers. Using Geographically Dispersed Parallel Sysplex (GDPS) between multiple data centers extends the failover capability between sites, which also drives efficiency by making capacity available on demand while leveraging LPARs that are already in use.
IBM’s strategic direction for the mainframe includes providing mainframe support for all the latest technologies, including WebSphere, Java, and Web services. These technologies are intrinsic to current IT imperatives such as Service-Oriented Architecture (SOA) and Web 2.0. This makes the mainframe even more suitable as a highly efficient server for current and future enterprise IT requirements.
The mainframe will continue to offer the best answer in terms of cost, greenness and the always-important Reliability, Availability and Scalability (RAS). IBM is continually offering smaller and more price-sensitive options, so even smaller enterprises can consider the mainframe.
Mainframe owners can effectively apply ITIL disciplines to optimize both the operational effectiveness and the energy efficiency of their computing environments. These twin gains will be essential for IT organizations to deliver maximum value to the business within increasingly challenging budget constraints. It’s critical for IT decision-makers to incorporate energy-consciousness into their ITIL processes; those who do so will find the mainframe a more compelling platform than ever for generating the greatest business value at the least cost.