MTTR and MTBF definitions?

MTTR and MTBF definitions?

• A. MTTR is mean time to repair; MTBF is mean time between fixes; they measure costs.
• B. MTTR is Mean Time To Recovery; MTBF is Mean Time Between Failures; they measure recovery speed and reliability.
• C. MTTR is maximum downtime; MTBF is minimum uptime; they measure capacity.
• D. MTTR is mean time to resume; MTBF is mean time before fix; they measure service availability.

Answer: (B)

MTBF and MTTR measure how dependable and maintainable a system is. MTBF, or mean time between failures, tells you how long the system runs before a failure occurs, reflecting reliability. MTTR, commonly called mean time to repair (often framed as time to recover or restore service), tells you how long it takes to fix the failure and bring the system back up, reflecting recovery speed and repair effectiveness. Together, they relate to availability: the longer the time between failures and the shorter the repair time, the higher the system’s availability. A handy way to estimate availability is MTBF divided by (MTBF plus MTTR). For example, if a system runs reliably for about 1000 hours on average and takes 2 hours to repair, availability is roughly 1000/(1000+2) ≈ 99.8%.

MTBF and MTTR measure how dependable and maintainable a system is. MTBF, or mean time between failures, tells you how long the system runs before a failure occurs, reflecting reliability. MTTR, commonly called mean time to repair (often framed as time to recover or restore service), tells you how long it takes to fix the failure and bring the system back up, reflecting recovery speed and repair effectiveness. Together, they relate to availability: the longer the time between failures and the shorter the repair time, the higher the system’s availability. A handy way to estimate availability is MTBF divided by (MTBF plus MTTR). For example, if a system runs reliably for about 1000 hours on average and takes 2 hours to repair, availability is roughly 1000/(1000+2) ≈ 99.8%.