CAP Theorem

Category: science

The principle that a distributed system can only provide two of three guarantees: Consistency, Availability, and Partition Tolerance.

CAP is the "distributed system reality check." You have to choose: Do you want data to be perfectly consistent (but slow/down if the network breaks), or do you want the system to be always available (but potentially serving slightly stale data)? You cannot have all three at once.

Common Examples

• Our system architecture prioritizes Availability and Partition Tolerance, accepting Eventual Consistency as a trade-off under the CAP theorem.
• The CAP theorem dictates that we cannot achieve absolute consistency while guaranteeing the 99.999% uptime required by our enterprise insurance clients.