Technology

Web & Application Tier

Within the SCA Architecture, web and application servers are automatically clustered and load-balanced. Capacity is automatically scaled up and down under high and low usage, and failures are automatically healed. The SCA architecture does not include an http caching layer, since in Engine Yard experience, it needlessly complicates the architecture while providing small performance benefits vs. well-configured Rails caching.

Web Server: Nginx

Nginx is a fast minimalist open source web server developed by Igor Sysoev, that now runs over 10 Million web sites. It supports all common web server functions including SSL, virtual hosts and SSIs. Nginx offers a smaller administration footprint that allows easier automation and management. It also offers extremely low response latency, lower resource consumption and marginally better bandwidth utilization.

Application Server: Passenger/Mongrel

Passenger and Mongrel are the standard Ruby on Rails application servers. Passenger was developed by Phusion, and Mongrel was originally written by Zed Shaw. Engine Yard automatically configures web and application clusters correctly with precise self-healing and clustering for optimal performance.

The Engine Yard web tier is secured behind a standard firewall. By default, only http, https and SSH ports are available.