Hi Khan,
The information which you put in the Deployment diagram has to be based how you meet the non functional requirements in the assignment.
like traffic/no. of users hitting the url at the same time, how the application responds during peak time, expected time for a page to be displayed blah blah blah. Your environment setup has to be handle these kind of situations.
A good and helpful blog on providing the level of details in Deployment diagram are provided here
http://java.dzone.com/articles/my-path-scea-5
Thanks,
Kumar.