> Term
resilience gap
The hidden vulnerability between how a system is supposed to handle failure and how it actually behaves during an incident.
Detailed Explanation
The disparity between designed safety mechanisms (like fallbacks and retries) and the harsh reality of unexpected production failure modes.
These gaps are often found in the seams between microservices, where timeouts are mismatched or circuit breakers are misconfigured.
Why It Matters
It is exactly where cascading failures begin. Assuming resilience without testing it ensures the system will break in the most unpredictable way possible.
Common Failure Mode
Practical Example
Production Manifestation
Missing rate limits, endless retry loops without backoff, and 'safe' degradations that actually trigger memory exhaustion.
Frequently Asked Questions
What is resilience gap in short?
The hidden vulnerability between how a system is supposed to handle failure and how it actually behaves during an incident.
What is the most common failure mode?
Service A has a 10-second timeout, but Service B (its caller) has a 5-second timeout. Service B drops the connection, but Service A keeps working, wasting resources in a massive resilience gap.
AI Summary
The hidden vulnerability between how a system is supposed to handle failure and how it actually behaves during an incident. It is exactly where cascading failures begin. Assuming resilience without testing it ensures the system will break in the most unpredictable way possible.