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Quiz

126 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 areas126 Architecture Fundamentals2 Distributed Systems26 Data Architecture23 Cloud Architecture19 Networking3 API & Integration Architecture1 Reliability & Resilience4 Observability3 Performance & Capacity Engineering3 Security Architecture16 Cost Architecture & FinOps3 Business Architecture2 Architecture Communication2 Enterprise Architecture1 Legacy Modernization2 AI-Era Architecture3 Software Architecture & Engineering3 Architecture Patterns3 Architecture Decision-Making6 The Architect's Meta-Skills1
Difficulty Any beginner intermediate advanced

20 questions in Distributed Systems.

  1. Backpressure & Flow Control advanced

    A worker's queue depth grows steadily through the day and never recovers. Adding workers helps for an hour, then it resumes. What is happening?

    2 min answer backpressurecapacityqueues
  2. Bulkheads & Isolation advanced

    A service calls four dependencies. How do you size its thread pools, and why is the total often smaller than people expect?

    2 min answer bulkheadpoolslittles-lawsizing
  3. Bulkheads & Isolation advanced

    You are asked to make a multi-tenant SaaS resilient to "any single failure". You propose cells. What must you find before that claim is true?

    2 min answer cellsisolationblast-radiusdependencies
  4. CAP & PACELC advanced

    Classify DynamoDB, Spanner and Cassandra under PACELC, and say which half of the classification you would actually design around.

    2 min answer pacelcconsistencylatencydatastores
  5. CAP & PACELC advanced

    You run active-active across two regions. The link between them fails. What should each region do, and what would you have designed differently?

    2 min answer partitionquorummulti-regionavailability
  6. Circuit Breakers advanced

    After adding circuit breakers, a partial outage now lasts three times longer than it used to. What is likely happening?

    1 min answer circuit-breakerrecoveryoscillation
  7. Distributed Locking advanced

    Three designs need distributed locks: a nightly report, a per-customer state machine, and a global config reload. For each, is a lock the right answer?

    2 min answer lockingpartitioningidempotencydesign
  8. Distributed Systems advanced

    A 43-second network partition caused GitHub over 24 hours of degraded service in 2018. How does a 43-second event become a day-long incident?

    2 min answer failoversplit-brainconsistencycase-study
  9. Distributed Systems advanced Multiple choice

    A card payment authorisation service runs active-active across two regions. A network partition splits them. Do you keep accepting authorisations, and what breaks either way?

    2 min answer capconsistencypaymentsavailability
  10. Distributed Systems 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 and how you would have prevented it.

    2 min answer cascading-failureretriestimeoutsresilience
  11. Distributed Transactions advanced

    Placing an order must reserve stock, charge the card and create a shipment across three services. Design it, and justify why not a distributed transaction.

    2 min answer sagatransactionspivotcompensation
  12. Event Streaming advanced Multiple choice

    Consumer lag on a Kafka topic grows during peak and does not recover overnight. You add consumers and nothing improves. Why?

    2 min answer kafkapartitionsconsumer-groupslag