> I need to implement a distributed environment which is scalable i. SOA
> based .

caboose published an interesting article on scaling up a rails app 
recently, it might give you some insight :

http://blog.caboo.se/articles/2007/7/29/scale-rails-from-one-box-to-three-four-and-five

> what webserver can i use ?

Twitter is a rails app that handles hundreds of requests per second. 
Some insights into their scaling issues are covered in this presentation 
:

http://www.slideshare.net/Blaine/scaling-twitter

Good luck !

Chris
-- 
Posted via http://www.ruby-forum.com/.