The architecture of Couchbase Server includes a built-in caching layer. This approach allows for very fast response times, since the data is initially written to RAM by the client, and can be returned from RAM to the client when the data is requested.
The effect of this design to provide an extensive built-in caching layer which acts as a central part of the operation of the system. The client interface works through the RAM-based data store, with information stored by the clients written into RAM and data retrieved by the clients returned from RAM, or loaded from disk into RAM before being returned to the client.
This process of storing and retrieving stored data through the RAM interface ensures the best performance. For the highest performance, you should allocate the maximum amount of RAM on each of your nodes. The aggregated RAM is used across the cluster.
This is different in design to other database systems where the information is written to the database and either a separate caching layer is employed, or the caching provided by the operating system is used to kept regularly used information in memory and accessible.