Canary in the Coal Mine
Noun Phrase · Slang & Abbreviations
Definitions
An early warning sign that points to a larger hidden problem. In engineering slang, a canary in the coal mine is usually a small failure or metric change that reveals a deeper system issue before the full blast arrives.
In plain English: An early warning signal for a bigger problem.
Example: "The spike in queue retries was the canary in the coal mine for a much broader storage latency problem that had not yet surfaced on the main dashboard."