Explain the CAP Theorem and its implications for system design.
This fundamental question tests your understanding of the trade-offs in distributed systems regarding Consistency, Availability, and Partition Tolerance. It is crucial for architecting robust solutions.
Why Interviewers Ask This
Interviewers use this to gauge your theoretical foundation in distributed systems. They want to see if you can make informed decisions about which properties to prioritize based on business requirements. It shows maturity in handling network failures and data synchronization.
How to Answer This Question
Define the three pillars: Consistency, Availability, and Partition Tolerance. Explain that you can only guarantee two out of three simultaneously. Provide examples of CP systems (like databases) and AP systems (like DNS). Discuss how modern systems often relax consistency for better availability.
Key Points to Cover
- Definition of C, A, and P
- Inevitability of partition tolerance
- Trade-off scenarios
- Real-world system examples
Sample Answer
The CAP Theorem states that a distributed system can only provide two out of three guarantees: Consistency, Availability, and Partition Tolerance. In practice, partition tolerance is non-negotiable due to network unrelia…
Common Mistakes to Avoid
- Misinterpreting the theorem as a binary choice
- Forgetting that partition tolerance is mandatory
- Confusing strong consistency with eventual consistency
Sound confident on this question in 5 minutes
Answer once and get a 30-second AI critique of your structure, content, and delivery. First attempt is free — no signup needed.