Jamie Allen - Effective Akka

This is one of those loose terms that, without context, might not mean much. For the sake of this book, I want to define high performance as the ability to handle tremendous loads very fast while at the same time being fault tolerant. Building a distributed system that is extremely fast but incapable of managing failure is virtually useless: failures happen, particularly in a distributed context (network partitions, node failures, etc.), and resilient systems are able deal with them. But no one wants to create a resilient system without being able to support reasonably fast execution.

You may have heard discussion, particularly around Typesafe, of creating reactive applications. My initial response to this word was to be cynical, having heard plenty of marketecture terms (words with no real architectural meaning for application development but used by marketing groups). However, the concepts espoused in the Reactive Manifesto make a strong case for what features comprise a reactive application and what needs to be done to meet this model. Reactive applications are characteristically interactive, fault tolerant, scalable, and event driven. If any of these four elements are removed, its easy to see the impact on the other three.

Akka is one of the toolkits through which you can build reactive applications. Actors are event driven by nature, as communication can only take place through messages. Akka also provides a mechanism for fault tolerance through actor supervision, and is scalable by leveraging not only all of the cores of the machine on which its deployed, but also by allowing applications to scale outward by using clustering and remoting to deploy the application across multiple machines or VMs.