  Cloud providers, like Amazon, offer their data centers' computational and
storage capacities for lease to paying customers. High electricity consumption,
associated with running a data center, not only reflects on its carbon
footprint, but also increases the costs of running the data center itself. This
paper addresses the problem of maximizing the revenues of Cloud providers by
trimming down their electricity costs. As a solution allocation policies which
are based on the dynamic powering servers on and off are introduced and
evaluated. The policies aim at satisfying the conflicting goals of maximizing
the users' experience while minimizing the amount of consumed electricity. The
results of numerical experiments and simulations are described, showing that
the proposed scheme performs well under different traffic conditions.
