With the increasing number of nodes in high performance clusters as well as the high frequency of the processors in these systems, energy consumption has become a key factor which limits their large-scale deployment. Most of the grid infrastructure is composed of clusters. EnergySaving is a middleware software that implements a power-on/power-o policy in order to save energy in a cluster setup. In this paper we present the rst experiences and test for using this software in a real environment. EnergySaving is currently under evaluation in the CETA-CIEMAT Grid Computing Center.

In order to obtain a estimate of the potential savings, a simulation tool has been developed. We use this tool with the experimental data of power consumption of the cluster nodes to estimate the savings due in the IT facilities of the cluster, in case the middleware was fully installed in a production environment. Finally a discussion of the combination of this tool with the gLite grid environment is presented.