A server has 30 days mean time between failure (MTBF) and 12 hours mean time to repair (MTTR). The availability of the server is approximately:
Pick an option to check yourself, or open the answer below.
Show answer & explanation
Correct answer: C. 98.3%
Explanation
Availability = MTBF / (MTBF + MTTR), with both terms in the same unit. Converting, MTBF = 30 days = 30 × 24 = 720 hours and MTTR = 12 hours. So availability = 720 / (720 + 12) = 720 / 732 = 0.9836, i.e. about 98.3%. A quick sanity check: the server is down 12 hours in every 732-hour cycle, which is roughly 1.6% downtime, matching 98.4% uptime. Option 3 is therefore correct.More Software Engineering questions
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