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2627 questions of the kind that actually get asked — in interviews, in architecture review boards, and by the person who has to run the thing at 3 AM. Every answer states the trade-off rather than the slogan, and says when the obvious choice is the wrong one.

All areas2627 Architecture Fundamentals81 Distributed Systems101 Data Architecture90 Cloud Architecture77 Networking86 API & Integration Architecture78 Reliability & Resilience88 Observability81 Performance & Capacity Engineering90 Security Architecture85 Cost Architecture & FinOps82 Business Architecture93 Architecture Communication91 Enterprise Architecture91 Legacy Modernization82 AI-Era Architecture86 Software Architecture & Engineering84 Architecture Patterns84 Architecture Decision-Making91 The Architect's Meta-Skills92 Delivery & Release Engineering93 Platform Engineering & Developer Experience92 Testing & Quality Architecture90 Data Platform Architecture88 Streaming & Real-Time Data93 Data Governance & Semantics81 Frontend & Experience Architecture91 Edge, Mobile & IoT88 Regulatory & Data Protection Architecture90 Assurance, Audit & Model Risk88
Difficulty Any beginner intermediate advanced

6 questions in Failure Modes.

  1. Failure Modes advanced

    A downstream service slows from 50 ms to 3 s. Within two minutes every service in the request path is down, including ones that do not call it. Explain the mechanism.

    2 min answer cascadingpoolslittle's-lawretries
  2. Failure Modes advanced

    A ride-hailing platform has a severe driver shortage in one region. Demand estimation, pricing, dispatch, queueing and driver incentives all interact. How do you prevent an unstable feedback loop?

    2 min answer olamarketplacefeedback-looppricing
  3. Failure Modes advanced

    One instance in a fleet of 20 is failing 30% of its requests. Health checks pass, aggregate error rate is 1.5%, no alerts fire. How do you detect and handle this?

    2 min answer gray-failureobservabilityresilience
  4. Failure Modes advanced

    One instance in a fleet of fifty is returning correct responses very slowly. Health checks pass and it stays in rotation. How do you detect and handle this?

    2 min answer grey-failurehealth-checksdetectionmitigation
  5. Failure Modes advanced

    Roblox's 2021 outage lasted 73 hours after a service-discovery and key-value cluster degraded under contention. Trace the failure chain, and identify the three architectural properties that turned a degradation into a three-day outage.

    2 min answer robloxconsulservice-discoverycascading-failure
  6. Failure Modes advanced

    What happens when a globally distributed real-time communication service loses an entire region - and how should DNS, health checks, traffic steering, failover, connection draining and data consistency interact?

    3 min answer failure-modesregional-failurefailoverdns