概念概述
值班轮换设计（On-Call Rotation Design）指的是：值班轮换设计在覆盖范围与可持续负载之间取舍，因为过度告警会侵蚀判断力并导致人员流失。
从更严格的定义看，On-call rotation design is the arrangement of who responds to alerts, for how long, and with what escalation, aiming to provide continuous coverage without exhausting responders. 该概念在工程实践中的价值，在于它能帮助团队用统一的语言描述一个具体的质量属性或设计约束，从而在评审与协作中减少歧义。
为什么需要它
It is central to any team that operates production systems and runs an incident response process. 它与 Incident Timeline Reconstruction、Heap Profiling、Centralised Log Aggregation 等概念经常一起出现，用于解决相近的工程问题。理解它的适用场景，有助于在多种备选方案之间做出有依据的取舍，而不是凭直觉选择技术方案。
常见误解
- a small rotation improves response time
- on-call is only about handling pages, not preventing them
需要避免的反模式
- scheduling one person permanently on call
- paging on issues that have no runbook or actionable response
实践要点
- Sustainable rotations spread nights and weekends across enough people and give responders time to recover, because judgement degrades quickly under repeated interruption.
- Every page should be actionable and documented; alerts without a clear response path should be removed or downgraded, which reduces fatigue.
- Handover between shifts and tracking page load over time expose whether the rotation is healthy or drifting toward burnout.