Capacity Management

Capacity Management is responsible for ensuring that the Capacity of the IT Infrastructure matches the evolving demands of the business in the most cost-effective and timely manner. The process encompasses:

• The monitoring of performance and throughput of IT Services and the supporting Infrastructure components.
• Undertaking tunning activities to make the most efficient use of existing resources.
• Understanding the demands currently being made for IT resources and producing forecasts for future requirements.
• Influencing the demand for the resource, perhaps in conjunction with Financial Management.
• The production of a Capacity Plan which enables the IT Service provider to provide services of the quality defined in Service Level Agreements (SLAs)  As shown in Figure 1, Capacity Management is essentially a balancing act; balancing.
• Cost against capacity: i.e. the need to ensure that processing Capacity that is purchased is not only cost justifiable in terms of business need, but also the need to make the most efficient use of those resources.
• Supply against demand: i.e. the need to ensure that the available supply of 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:

Figure 1 Capacity Management – a balancing act

Why Capacity Management?

Capacity Management is often proclaimed as old-fashioned, mainframe-oriented discipline. IT Services Managers in charge of distributed computing facilities have argued that Capacity Management takes more time and effort, and the, therefore, cost than it is worth and that it would be better to pay for upgrades as required. IT organisations with this view tend to exhibit the following symptoms:

• Procurement of IT equipment is justified on an individual capital return basis, rather than the overall corporate requirement.
• There are no corporate Capacity Plans
• No business Capacity forecasts are produced
• Network Capacity Management is done reactively
• Capacity Management of servers is also done reactively albeit less often
• Little or no Capacity Management is performed on desktop equipment

Managing the capacity of large networks of distributed equipment is more complex than in the ‘good old days’ of the mainframe and for all thriving organisations, the financial investment in IT is increasing. Therefore it makes even more sense to plan for growth. While the cost of the upgrade to a compone in a mainframe environment, there are often many more components in the distributed environment that need to be upgraded. Also, there could now be economies of scale, because of the cost per individual component could be reduced when many components need to be purchased. So Capacity Management should have input into the process to ensure that the best deals with suppliers are negotiated.

A corporate Capacity Management process ensures that the entire organisations Capacity requirements are catered for. The cost of upgrading all the desktop equipment in an organisation could easily exceed the cost of a mainframe upgrade. Capacity Management should have responsibility for the ‘refresh policy’ ensuring that desktop equipment has sufficient Capacity to run the applications that the business requires for the foreseeable future.