This document discusses using RFX (Reactive Function X), a design pattern and collection of open source tools, to solve fast data problems. It presents an example of using RFX for web analytics to count pageviews and unique users and detect DDOS attacks. The RFX approach applies the BEAM methodology for agile data warehousing. It demonstrates RFX concepts like event data actors, agents, collectors, routers, processors, storage and reactors using a pageview analytics demo with source code on GitHub.