CAP Theorem

Background

In distributed systems, different types of failures can occur, e.g., servers can crash or fail permanently, disks can go bad resulting in data losses, or network connection can be lost, making a part of the system inaccessible. How can a distributed system model itself to get the maximum benefits out of different resources available?

Solution

CAP theorem states that it is impossible for a distributed system to simultaneously provide all three of the following desirable properties:

Consistency ( C ): All nodes see the same data at the same time