Cap Theorem easy
Why is a CA (Consistent + Available) system generally considered impossible for distributed web applications?
- A Maintaining both C and A requires more CPU cycles than modern server hardware can currently provide.
- B The synchronization of data across multiple geographic regions violates the fundamental laws of physics.
- C Networks are inherently unreliable and partitions are inevitable; assuming P never occurs leads to catastrophic failure.
- D Modern database engines lack the internal locking mechanisms required to support simultaneous C and A.
Answer: C. Networks are inherently unreliable and partitions are inevitable; assuming P never occurs leads to catastrophic failure.
Partition Tolerance (P) is not an architectural 'choice' but a reality of distributed networking. Cables can be cut, and routers can fail. If a system claims to be 'CA', it is effectively ignoring the possibility of a partition. When a partition inevitably occurs, such a system must either drop Consistency or drop Availability to resolve the split. True 'CA' systems can only exist on a single, non-distributed machine.
One system design question a day, with spaced repetition so the ones you miss come back.
Get the appRelated questions
- What is a 'Split Brain' scenario?
- The PACELC theorem extends CAP by stating: Even when there is NO partition (E), the system must choose between:
- In CAP, 'Consistency' is equivalent to:
- In the CAP Theorem, what does the 'P' stand for?
- What causes a Network Partition?
- Which system would likely prioritize Consistency over Availability (CP)?