MTTF, MTTR, MTBF

Definition: Measures the average time the software operates before encountering a failure.
Formula: MTTF=Total Time of Operation / Number of Failures
Purpose: To assess the reliability of the software product. A higher MTTF indicates a more reliable system.
Usage: Used in mission-critical systems where uptime is crucial (e.g., medical, aerospace, or financial applications).
Example: If a system runs for 1,000 hours and fails 5 times, the MTTF is 200 hours per failure.

Definition: Measures the average time required to fix a defect or failure in the system.
Formula: MTTR=Total Downtime / Number of Failures
Purpose: To evaluate how quickly the team can resolve issues. A lower MTTR means faster recovery from failures.
Usage: Helps teams assess their incident response efficiency and improve support and maintenance.
Example: If a system is down for 10 hours due to 5 failures, the MTTR is 2 hours per failure.

Definition: Measures the average time between two consecutive failures of the software.
Formula: MTBF=MTTF+MTTR
Purpose: To assess the stability and robustness of the software over time. A higher MTBF means a more stable and reliable system.
Usage: Critical for systems that require high availability (e.g., banking, telecommunications, or cloud-based platforms).
Example: If a system fails every 100 hours and takes 2 hours to repair, the MTBF is 102 hours.