Modern OLAP Systems
With modern OLAP systems, you replace your Traditional OLAP Cubes one-to-one with another technology. Therefore, you keep everything the same on your current architecture but replace your cubes with a modern big data-optimized technology that focuses on the fastest query response time. See the Appendix for a comparison between modern OLAP Technologies.
# Open-Source Tools
Check more on Traditional OLAP Cube Replacements.
References: Apache Druid