Unicorn, Nginx and Webrick/Mongrel for what?


I am trying to find out what Unicorn/Ngnix does and how they work on
Rails application deployment. (I guess they are meaningful for

For Rails server, I think we can use WebRick or Mongrel.
And for what do we need to use Unicorn?
And Unicorn should come along with Nginx?

I am a newbie to Rails app deployment and server management.
I’d much appreciate if you will walk me through the answers to above

Thanks in advance,

This article explains how all the components are related to each other:

If you’re new to Rails deployment then using Nginx + Phusion Passenger
(instead of Nginx + Unicorn) is a much easier solution.