RSS Feed Subscribe to RSS Feed


Why to avoid Mean Time to Recover (MTTR)

The 2022 Void Report came out in late 2022, It is a recommended read, and I previously summarized it here. This article focuses on one aspect of the report: why mean time to recover (MTTR) is not an appropriate metric for complex software systems.

The takeaway are:

  • Do track time to recover (TTR) for each incident. It can be a useful exercise to think about when an incident started and stopped. That can help when calculating the cost of an incident.
  • Don’t report those times in aggregate, such as MTTR. Systems fail in non-uniform ways and averaging numbers to represent their reliability (or the performance of the supporting teams) is likely to be misleading.
  • Instead, use:
    • Post-incident learning reviews to learn (and share!) everything you can from an incident
    • SLOs to help align technical system metrics with business objectives
    • Consider sociotechnical incident data too


Tags: , , , , , , ,