Cassandra

Cassandra is used as the primary database in HIE. Cassandra was chosen for its simplicity of setup, horizontal scaling capability. It is also read optimized to enable faster reads. Cassandra can handle huge volumes of data and provide good read/writes. Cassandra cluster is recommended to be setup. Also the cluster size needs to be decided on the data volume.

When the data size goes up, a new cassandra nodes can also be added easily. Refer this for more information on Cassandra. And here for how to add new nodes to Cassandra.

Some useful Cassandra maintenance tools can be found here.

Cassandra troubleshooting guide can be found here.