The Decision Data Store service stores data in JSON format for each customer from the sources configured to write to the Decision Data Store through data set instances. The data is distributed and replicated around the cluster of decision data nodes, and stored in the file system of each decision data node in a Cassandra database.
To optimize the performance of operations on customer data, the data for a specific customer is stored on the same node even if the data is on different nodes. You can add extra Decision Data Store nodes to increase the volume of data that is handled by your decision management processes or to reduce latency in making decisions.