VietMX Staff asked 3 years ago
Availability refers to the probability that a system performs correctly at a specific time instance (not duration). Interruptions may occur before or after the time instance for which the system’s availability is calculated. The service must be operational and adequately satisfy the defined specifications at the time of its usage.
Availability is often quantified by uptime (or downtime) as a percentage of time the service is available. Availability is generally measured in number of 9s–a service with 99.99% availability is described as having four 9s.
