Storage glossary · JSON corpus · llms.txt · hesela.com

gray-failure · unknown · also grey failure

Gray failure

A gray failure occurs when an application observes a system as unhealthy while that system's failure observer regards it as healthy.

Related Observatory article: Gray failure on hesela.com

This observer-relative definition is broader than slow hardware: it can include intermittent errors and capacity problems. A slowdown detected by both observers need not be gray in this sense. [1]

Relations

related
fail-slow, differential-observability

Citations

  1. Huang et al., Gray Failure: The Achilles' Heel of Cloud-Scale Systems, HotOS 2017, section 3; DOI 10.1145/3102980.3103005. (accessed 2026-10-13)
  2. Hesela: Fail-slow NVMe SSDs: what SMART and heartbeats miss (accessed 2026-10-13)

JSON: /data/terms/gray-failure.json