Which statement about MTBF is true?

Which statement about MTBF is true?

• A. MTBF measures mean time to repair.
• B. MTBF measures uptime percentage.
• C. MTBF is sufficient on its own for reliability planning.
• D. MTBF measures average time between failures but not impact or recovery; must be paired with RTO/RPO and MTTR.

Answer: (D)

MTBF represents the average time the system operates between failures. It tells you how often failures happen, not how severe a failure is or how long it takes to recover. Because downtime is described by MTTR (mean time to repair), you typically look at MTBF together with MTTR to understand overall reliability and availability. The availability of a repairable system can be approximated by MTBF divided by (MTBF plus MTTR). In business continuity terms, you also consider RTO (recovery time objective) and RPO (recovery point objective) to ensure outages don’t violate operational or data-loss requirements. That combination—MTBF for how often failures occur, MTTR for how long it takes to recover, and RTO/RPO for acceptable outage impact—is why this statement is the best fit: MTBF measures average time between failures but not the impact or recovery by itself; it needs MTTR and often RTO/RPO to inform planning.

MTBF represents the average time the system operates between failures. It tells you how often failures happen, not how severe a failure is or how long it takes to recover. Because downtime is described by MTTR (mean time to repair), you typically look at MTBF together with MTTR to understand overall reliability and availability. The availability of a repairable system can be approximated by MTBF divided by (MTBF plus MTTR). In business continuity terms, you also consider RTO (recovery time objective) and RPO (recovery point objective) to ensure outages don’t violate operational or data-loss requirements. That combination—MTBF for how often failures occur, MTTR for how long it takes to recover, and RTO/RPO for acceptable outage impact—is why this statement is the best fit: MTBF measures average time between failures but not the impact or recovery by itself; it needs MTTR and often RTO/RPO to inform planning.