Capacity and Availability Management (CAM) (CMMI-SVC)

The Capacity and Availability Management process area involves establishing and maintaining capacity and availability at a justifiable cost and with an efficient use of resources. Capacity and availability management activities can be performed at different levels of the organization, including across different services.

The Capacity and Availability Management process area involves the following activities:

• Establishing and maintaining a capacity and availability management strategy
• Providing and allocating resources appropriately
• Monitoring, analyzing, understanding, and reporting on current and future demand for services, use of resources, capacity, service system performance, and service availability
• Determining corrective actions to ensure appropriate capacity and availability while balancing costs against resources needed and supply against demand

“Capacity” is the degree to which one thing can support, hold, process, or produce another thing. In the context of services, capacity can refer to the maximum amount of service delivery or maximum number of service requests that a service system can handle successfully within a fixed period of time. Capacity is a quality attribute. The definition and measurement of capacity can differ for different types of services and service systems and can be defined in the service agreement. In addition, capacity definitions and measures can be derived from service agreements, rather than reflected there. If the service agreement has no explicit capacity requirements, it may still imply derived capacity requirements for the service or service system. For some services, capacity can be the maximum size, volume, or throughput of service system components.

 

As part of establishing the capacity and availability management strategy, the following are determined:

• Resources appropriate to manage
• Aspects of the service system that affect service availability and should be measured, monitored, analyzed, and managed

 

“Availability” is the degree to which something is accessible and usable when needed. In the context of services, availability can refer to the set of times, places, and other circumstances in which services are to be delivered, service requests are to be honored, or other aspects of a service agreement are to be valid. Availability is a quality attribute. Different work groups can have different definitions and measurements of availability for different types of services and service systems and for various perspectives of availability (e.g., business perspective, end-user perspective, customer perspective, service provider perspective). The definition of availability requires an understanding of how service system components support service requirements for availability, which can be defined in the service agreement. In addition, availability requirements and measures can both depend on and affect other closely related quality attribute requirements, such as maintainability, reliability, sustainability, and security.

 

Availability is one of the most visible indicators of service quality in the eyes of the end user and customer. For some services, understanding the relationships among attributes such as reliability and maintainability and availability is important to managing availability.

 

“Capacity management” is focused on how best to provide resources to meet service requirements. “Availability management” is focused on delivering a sustained level of availability to meet service requirements. However, at a high level, many of the best practices for capacity management and availability management are similar enough to be combined, and they become closely coupled. Capacity management provides the means for achieving sustained availability to meet service requirements. (For some services, it provides spare capacity and resilience as well.)

The simultaneous production and consumption of services is one of the unique characteristics of services. This characteristic presents some challenges for managing the capacity and availability of services. If the capacity and availability to provide the service is not present when demand occurs, the customer must wait, resulting in costs of one kind or another (e.g., lower customer satisfaction, lost business as customers give up on waiting, financial penalties). Costs can also be associated with excess capacity when estimated demand does not occur (e.g., cost of staff on the payroll sitting idle, purchasing costs of excess capacity).

 

 

Capacity and availability management includes establishing service system representations and using these representations for the following:

• Supporting negotiation of appropriate service agreements
• Planning
• Making decisions
• Considering corrective actions
• Providing and allocating resources to meet current and future service requirements

“Service system representations,” such as models, simulations, diagrams, maps, and prototypes, provide insight into how a service system will behave given specific work volumes and varieties. These representations can be built using spreadsheets, commercial off-the-shelf (COTS) tools (e.g., simulation packages), or tools developed in house. For some services, the representations can be known as historical baselines, trend analyses, analytical models, analysis of waiting times in queues, simulation models, statistical models (e.g., regression models, time series models), causal models (e.g., probabilistic networks), or application sizing.

The scope of capacity and availability management can be one service system or multiple service systems. If the service provider is operating multiple service systems, capacity and availability management processes can be performed independently on each discrete service system but the organization may realize reduced value.