Availability¶
The systems engineering body of knowledge defines availability as the
"… probability that a repairable system or system element is operational at a given point-in-time under a given set of environmental conditions"
Herein, define the system's availability expectations. Availability is a function of reliability and maintainability, i.e.,
\[
availability = \frac{MTBF}{MTBF + MTTR}
\]
whereby
- The mean time between failure is a reliability metric.
- The mean time to repair is a maintainability metric.
