Quiz

2667 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 areas2667 Architecture Fundamentals81 Distributed Systems101 Data Architecture90 Cloud Architecture87 Networking86 API & Integration Architecture78 Reliability & Resilience88 Observability81 Performance & Capacity Engineering90 Security Architecture95 Cost Architecture & FinOps92 Business Architecture93 Architecture Communication91 Enterprise Architecture91 Legacy Modernization92 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

90 questions in Performance & Capacity.

Quiz

A page makes 20 parallel backend calls, each with a p99 of 1 second and a p50 of 40 ms. What is the page's latency profile?

A downstream call goes from 50 ms to 3 seconds at constant traffic. Use Little's Law to explain what happens to the caller and why services that never call it also fail.

A platform must size worker pools for a peak of 50,000 requests per second with a 200ms average service time. How does Little's Law inform the answer, and what does it not tell you?

A service's latency rises sharply while throughput plateaus and CPU sits at 50%. Use queueing theory to explain what is happening and what to measure next.

An API platform has an average of 400 requests in flight and processes 2,000 requests per second. What is the average latency, and how is Little's Law used for capacity decisions?

A commerce platform load tests successfully at five times peak traffic, then fails during the real peak event. What is typically wrong with the load test?

A load test passed at 3x expected traffic and production fell over at 1.2x. Name four ways the test could have been unrealistic.

A retail platform's load tests pass comfortably and production fails at the same throughput during a sale. What is different about production?

An annual sale will bring 10× normal traffic in a 72-hour window. What preparation should begin months in advance, and what is prepared but hopefully never used?

Your load tests pass consistently and production still falls over at peak. What is wrong with the tests?

A client library opens a new HTTPS connection for every request. One host sends 2,000 requests per second to a single destination endpoint. What breaks first, and in what order does everything else follow?

A content platform finds that transfers to distant clients achieve far less throughput than the available bandwidth. What are the causes and what tuning applies?