Some books and articles on server performance, optimizing, modeling that I recommend. Read or planing to read them:
1.) The bible of Performance in general, focusing on the Web:
by Daniel A. Menasce, Lawrence W. Dowdy, Virgilio A.F. Almeida
2.) An original and [almost] funny book about performance, capacity planning, queuing networks, etc. Proposes the “Universal Scalability Law”, still need to test it, anyway, the book:
Guerrilla Capacity Planning: A Tactical Approach to Planning for Highly Scalable Applications and Services
by Neil J. Gunther from Perfdynamics, a must!
More coming soon, need to give credit to the gurus!