Cassandra 3.x High Availability - Second Edition

Monolithic simplicity

The simplest design approach to guarantee ACID properties is to implement a monolithic architecture where all functions reside on a single machine. Since no coordination among nodes is required, the task of enforcing all the system rules is relatively straightforward.

Increasing availability in such architectures typically involves hardware layer improvements, such as RAID arrays, multiple network interfaces, and hot-swappable drives. However, the fact remains that even the most robust database server acts as a single point of failure. This means that if the server fails, the application becomes unavailable. This architecture can be illustrated with the following diagram:

A common means of increasing capacity to handle requests ...