Phusion has released Phusion Passenger Enterprise 4.0 beta 1. According to the website, this version includes improved scalability and concurrency as well as dramatically improved internal architecture.

According to the project website, “Phusion Passenger is an Apache and Nginx module for deploying Ruby and Python web applications. It has a strong focus on ease of use, stability and performance. Phusion Passenger is built on top of tried-and-true, battle-hardened Unix technologies, yet at the same time introduces innovations not found in most traditional Unix servers.”

The changes in Phusion Passenger 4 include support for multiple Ruby versions, Python WSGI support, multithreading, improved zero-copy architecture, better error diagnostics, and support for JRuby, and Rubinius. This means you can now run multiple Ruby versions at the same time in the same Phusion Passenger instance. Additionally, Phusion Passenger’s I/O handler has been completely rewritten and is now “evented” just like Nginx and Node.js.

Phusion Passenger 4 also introduces real-time response buffering. Unlike traditional response buffering, Phusion Passenger sends data to the client immediately, while still relieving the application from slow clients, the website said.