With the increased complexity of platforms, the growing demand of applications and data centers' servers sprawl, power consumption is reaching unsustainable limits. The need to improved power management is becoming essential for many reasons including reduced power consumption & cooling, improved density, reliability & compliance with environmental standards. This paper presents a theoretical framework and methodology for autonomie power and performance management in e-business data centers. We optimize for power and performance (performance/watt) at each level of the hierarchy while maintaining scalability. We adopt mathematically-rigorous optimization approach minimizing power while meeting performance constraints. Our experimental results show around 72% savings in power as compared to static power management techniques and 69.8% additional savings with both global and local optimizations.