Availability is the proportion of time a system is operational and able to perform its function, usually expressed as a percentage such as 99.999 percent. Mathematically it relates to reliability and repair time as MTBF divided by the sum of MTBF and MTTR. It is the core metric behind data center uptime commitments and Tier classifications.
Category: Resilience & Availability · Subcategory: Business Continuity · Part of the AIDC Technical Terminology reference.