Web search engines are widely used by everyone in the world. They are searching their each and every query through search engines. As a result, the number of users increases day by day. When the users increase, there is a need to increase the data centers and servers that holds the data. There may be some allocation or scheduling for every server in the data centers. When more number of users tries to search for a same query, the processing load increases results in CPU overhead. In order to overcome this problem, in this book we are introducing Predictive Energy Saving Online Scheduling Algorithm (PESOS) in web search engines not in the web servers.