Introduction to the CAP Theorem
In distributed systems, achieving perfect reliability is challenging due to network issues, node failures, and data replication across multiple locations. The CAP Theorem, proposed by Eric Brewer in 2000, states that in the presence of a network partition, a distributed system can only guarantee two out of three properties: Consistency, Availability, and Partition Tolerance.
This theorem highlights fundamental trade-offs in system design, especially relevant after learning about auto-scaling and monitoring in distributed environments.
Key insight: No system can be CA, CP, or AP simultaneously when partitions occur—designers must choose based on application needs.
For example, in a banking system, strong consistency might be prioritized over availability during network issues to prevent overdrafts.