How to calculated hardware requirement for Openfire Server
I´m too interested in this question.
This topic comes up on the forums many, many times. Did you try searching the forum first?
Your question is too vague to answer. What number of users are you going to have? What will the users be doing? How much MUC activity? How many buddies? Will you use shared rosters? Gateways? Will the database be on the same machine?
There is no magic formula for hardware and openfire. In general, you want to have at least 512 MB to dediate to openfire and some modern processor.