問46
頻出度★★★
ITサービスに関する指標には, ITサービスが利用できなくなるインシデントの発生間隔の平均時間であるMTBSI (Mean Time Between Service Incidents) があり, サービスの中断の発生しにくさを表す。ITサービスにおいてMTBSIの改善を行っている事例として, 最も適切なものはどれか。
令和5年度 ITパスポート試験 問46
マネジメント系サービスマネジメント › サービスマネジメントシステム
This question's explanation and your answers so far.
解説
問 46
Incorrectア
A measure that builds and analyzes a database of incident-response cases to shorten the time from an interruption to identifying its cause. This concerns the speed of recovery and restoration after an interruption occurs, namely MTRS (Mean Time to Restore Service) or MTTR, and does not lengthen the interval between incidents. It is not an improvement of MTBSI.
Incorrectイ
A measure that increases the service menu (offerings) to grow the number of users, which is about service expansion and the sales side. It has nothing to do with the frequency or interval of incidents (interruptions) and is not connected to improving MTBSI.
- ウ
正解 MTBSI is the average interval between incidents that make a service unavailable, and improving it means lowering the frequency of incidents themselves so that the interval becomes longer. Choice ウ duplicates (makes redundant) the configuration of the network that provides the service, reducing failures in which the network becomes unreachable. When the number of failures drops, the interval until the next incident lengthens and MTBSI grows larger. This is an availability-improvement measure that directly makes interruptions less likely to occur, and is the most appropriate example of improving MTBSI.
Incorrectエ
A measure that increases help-desk staff to shorten the waiting time for inquiries. This concerns the response time of user support and does not lower the frequency of incidents that make the service unavailable. It is an improvement related to the efficiency of customer support, not MTBSI.
ここがポイント
- MTBSI (Mean Time Between Service Incidents) is the interval between incidents; the larger the value, the less likely a service interruption is. Improvement = lowering the frequency and lengthening the interval. Availability-improvement measures that reduce failures themselves, such as redundancy, apply.
- The interval between occurrences (MTBSI) and the time to recovery (MTRS / MTTR) are different metrics. Shortening the time for cause investigation or restoration belongs to recovery-type metrics and should be distinguished from improving MTBSI.
用語