Which of the following concepts is used to determine how maintainable a system or device is?

The average time required to repair a system or device in the event of a failure is referred to as the mean time to repair (MTTR). As part of business continuity planning, MTTR is utilized to determine if a system necessitates additional redundancy or other solutions if the time to repair and recover surpasses the maximum acceptable outage. MTTR is determined by dividing the total maintainable time by the total number of repairs. Mean time between failures (MTBF), meantime to fail (MTTF), and man-in-the-middle (MITM) is an on-path attack, a term that has been increasingly replaced with on-path.