What does 'availability' refer to in the context of IT services?

In the context of IT services, 'availability' specifically refers to the proportion of time a system is operational and accessible to users. This concept is crucial for ensuring that users can access the services and resources they need without interruption. High availability is a key aspect of service level agreements (SLAs) and is vital for maintaining user satisfaction and business continuity.

When systems are designed with availability in mind, they often incorporate redundancy, failover mechanisms, and regular maintenance protocols to minimize downtime. Thus, defining availability in terms of the operational time of a system directly aligns with the expectations for delivering reliable IT services.

While cost-effectiveness, performance under load, and user capacity are all important factors in assessing IT systems, they do not capture the essence of availability, which is fundamentally about ensuring continuous access to services.