About Availability Management
The purpose of availability management as a practice is to ensure that services deliver the agreed levels of availability to meet the needs of customers and users.
Availability management ensures that requirements for the availability of services and resources are understood and fulfilled efficiently and in line with the organization’s strategy and commitments. To enable this, availability management is applied throughout the organization’s product and service lifecycle from ideation to operations.
Availability management plays a pivotal role when products and services are planned and designed. Decision made during the planning and design stage will affect availability levels and related constraints, along with the organization’s ability to monitor and manage these aspects.
Availability is a critical service characteristic from a service consumers perspective, and is therefore subject to negotiation, agreement, monitoring and relevant reporting. Many other Service Management Practices (such as business analysis, relationship management, service design, service level management, and measurement and reporting, to name but a few) are involved and supports the availability management practice to ensure availability is consistently and sufficiently addressed.
What is availability?
ITIL defines availability as the ability of an IT service or other configuration item to perform its agreed function when required.
In theory, and in legacy service management consideration, availability is simple to measure and understand. It depends on how frequently a service fails and how quickly it recovers after a failure. These are often expressed as mean time between failures (MTBF) and mean time to restore service (MTRS).
In practice though, availability management is a complex characteristic. To measure and to understand, multiple measurements and agreements about how these measurements should be understood in the context of a service are needed. Availability depends on the service architecture, importance of certain service components or service actions, criteria of unavailability, service hours and other parameters.
The availability management practice should ensure a transparent, consistent and practical understanding of availability among all relevant parties. When a service is provided (consider an application) to thousands or millions of people, there is not usually a single generic availability agreement with customers, but the overall service availability is critical for the service provider.
Availability is closely connected to service performance, capacity, continuity and information security.
As a result Service Availability is central to business success.