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Value to the business. Capacity Management is responsible for ensuring that IT resources are planned and scheduled to provide a consistent level of service that is matched to the



Capacity Management is responsible for ensuring that IT resources are planned and scheduled to provide a consistent level of service that is matched to the current and future needs of the business, as agreed and documented within SLAs and OLAs. In conjunction with the business and their plans, Capacity Management provides a Capacity Plan that outlines the IT resources and funding needed to support the business plan, together with a cost justification of that expenditure.

4.3.4 Policies/principles/basic concepts

Capacity Management ensures that the capacity and performance of the IT services and systems matches the evolving agreed demands of the business in the most cost-effective and timely manner. Capacity Management is essentially a balancing act:

  • Balancingcostsagainstresourcesneeded: the need to ensure that processing capacity that is purchased is cost-justifiable in terms of business need, and the need to make the most efficient use of those resources.
  • Balancing supply against demand: the need to ensure that the available supply of IT processing power matches the demands made on it by the business, both now and in the future. It may also be necessary to manage or influence the demand for a particular resource.

Capacity Management processes and planning must be involved in all stages of the Service Lifecycle from Strategy and Design, through Transition and Operation to Improvement. From a strategic perspective, the Service Portfolio contains the IT resources and capabilities. The advent of Service Oriented Architecture, virtualization and the use of value networks in IT service provision are important factors in the management of capacity. The appropriate capacity and performance should be designed into services and components from the initial design stages. This will ensure not only that the performance of any new or changed service meets its expected targets, but also that all existing services continue to meet all of their targets. This is the basis of stable service provision.

The overall Capacity Management process is continually trying cost-effectively to match IT resources and capacity to the ever-changing needs and requirements of the business. This requires the tuning and optimization of the current resources and the effective estimation and planning of the future resources, as illustrated in Figure 4.8.

Figure 4.8 The Capacity Management process

Capacity Management is an extremely technical, complex and demanding process, and in order to achieve results, it requires three supporting sub-processes.

One of the key activities of Capacity Management is to produce a plan that documents the current levels of resource utilization and service performance and, after consideration of the Service Strategy and plans, forecasts the future requirements for new IT resources to support the IT services that underpin the business activities. The plan should indicate clearly any assumptions made. It should also include any recommendations quantified in terms of resource required, cost, benefits, impact, etc.



The production and maintenance of a Capacity Plan should occur at pre-defined intervals. It is, essentially, an investment plan and should therefore be published annually, in line with the business or budget lifecycle, and completed before the start of negotiations on future budgets. A quarterly re-issue of the updated plan may be necessary to take into account changes in service plans, to report on the accuracy of forecasts and to make or refine recommendations. This takes extra effort but, if it is regularly updated, the Capacity Plan is more likely to be accurate and to reflect the changing business need.

The typical contents of a Capacity Plan are described in Appendix J.

4.3.4.1 Business Capacity Management

This sub-process translates business needs and plans into requirements for service and IT infrastructure, ensuring that the future business requirements for IT services are quantified, designed, planned and implemented in a timely fashion. This can be achieved by using the existing data on the current resource utilization by the various services and resources to trend, forecast, model or predict future requirements. These future requirements come from the Service Strategy and Service Portfolio detailing new processes and service requirements, changes, improvements, and also the growth in the existing services.

4.3.4.2 Service Capacity Management

The focus of this sub-process is the management, control and prediction of the end-to-end performance and capacity of the live, operational IT services usage and workloads. It ensures that the performance of all services, as detailed in service targets within SLAs and SLRs, is monitored and measured, and that the collected data is recorded, analysed and reported. Wherever necessary, proactive and reactive action should be instigated, to ensure that the performance of all services meets their agreed business targets. This is performed by staff with knowledge of all the areas of technology used in the delivery of end-to-end service, and often involves seeking advice from the specialists involved in Component Capacity Management. Wherever possible, automated thresholds should be used to manage all operational services, to ensure that situations where service targets are breached or threatened are rapidly identified and cost-effective actions to reduce or avoid their potential impact implemented.

4.3.4.3 Component Capacity Management

The focus in this sub-process is the management, control and prediction of the performance, utilization and capacity of individual IT technology components. It ensures that all components within the IT infrastructure that have finite resource are monitored and measured, and that the collected data is recorded, analysed and reported. Again, wherever possible, automated thresholds should be implemented to manage all components, to ensure that situations where service targets are breached or threatened by component usage or performance are rapidly identified, and cost-effective actions to reduce or avoid their potential impact are implemented.

There are many similar activities that are performed by each of the above sub-processes, but each sub-process has a very different focus. Business Capacity Management is focused on the current and future business requirements, while Service Capacity Management is focused on the delivery of the existing services that support the business, and Component Capacity Management is focused on the IT infrastructure that underpins service provision. The role that each of these sub-processes plays in the overall process and the use of management tools is illustrated in Figure 4.9.

Figure 4.9 Capacity Management sub-processes

The tools used by Capacity Management need to conform to the organization’s management architecture and integrate with other tools used for the management of IT systems and automating IT processes. The monitoring and control activities within Service Operation will provide a good basis for the tools to support and analyse information for Capacity Management.





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