ITPEC FE Morning April 2020 Question 55
In ITIL, the reduction in the index value expressing maintainability is cited as an example of a key performance index (KPI) in availability management. Which of the following corresponds to such an index?
Explanation
Mean time to restore service (MTRS) — maintainability is how quickly a failed service is brought back, so a shorter MTRS is the improvement.
ITIL availability management tracks three aspects of a service. Reliability is how long it runs without failing, measured by MTBF and MTBSI, where higher is better. Maintainability is how fast it is restored after a failure, measured by MTRS, where lower is better. Availability combines the two. A KPI stated as a reduction in a maintainability index therefore refers to MTRS.
Answer (c)
Why not others:
- •(a) Mean time between failures — measures reliability, and the goal is to increase it, not reduce it
- •(b) Mean time between service incidents — also a reliability measure (MTBF plus the restoration time); a longer interval is better
- •(d) Number of interruptions — counts how often the service fails, which reflects reliability, not how fast it is restored
Key rule: Time between failures measures reliability and should grow; time to restore measures maintainability and should shrink.
Service Management · AI-written, may contain errors
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