You can refer to the following references for more information:
- CSI: https://medium.com/google-cloud/understanding-the-container-storage-interface-csi-ddbeb966a3b
- StatefulSet: https://kubernetes.io/docs/concepts/workloads/controllers/statefulset/
- Cassandra: https://cassandra.apache.org/
- Redis: http://redis.io/
- Latency numbers every programmer should know: https://gist.github.com/jboner/2841832