uptimeavailability

Uptimeavailability is a composite metric used in information technology to describe the proportion of time a system is both operational and able to perform its intended functions. It combines concepts of uptime and availability to reflect the extent to which a component, service, or platform is accessible to users.

The standard definition expresses availability as A = Uptime / Total Time. Uptime is the time the system is online and functioning, while Total Time is the observation period. In reliability terms, availability may be calculated as MTBF / (MTBF + MTTR). Many organizations report uptimeavailability as a percentage over a defined window, such as a calendar month.

Planned maintenance can be treated as downtime or excluded depending on policy. Uptimeavailability is influenced by redundancy, failover mechanisms, maintenance practices, and system architecture. Downtime categories include unplanned outages and scheduled maintenance, while partial outages may reduce service levels without complete failure.

Measurement and reporting rely on monitoring, incident records, and service dashboards. Common targets include 99.9% (four nines) and 99.99% (five nines). The metric supports service level agreements and capacity planning but should be interpreted alongside performance metrics and user experience.

Limitations include varying definitions across organizations and the fact that uptimeavailability does not capture degraded performance during online periods. It is related to, but distinct from, measures of reliability, maintainability, and overall service reliability.