AN APPLICATION-ORIENTED POWER CONSUMPTION MODEL OF STORAGE SERVERS

The electric power consumption of each information system has to be reduced in order to realize green societies. In information systems, clients issue requests to servers and the servers spend electric power to handle the requests. We have to reduce the power consumption of servers since servers mainly consume electric power compared with clients. There are computation (CP), communication (CM), and storage (ST) types of applications to be performed on servers. In CP and CM applications, CPU and communication resources are mainly consumed, respectively. In this paper, we consider ST applications where files in storage drives are manipulated on a server. First, we measure the power consumption rate of a server to perform processes in ST and CP applications. Here, there are read (R), write (W), and computation (C) types of processes which just read files, write files, and do computation, respectively. Then, we discuss a power consumption model of a server by abstracting most essential parameters dominating the power consumption of the server from the experimental results. Here, the power consumption rate of a server is maximum if at least one process is performed. The maximum power consumption rate of a server depends on types of processes concurrently performed on the server. We discuss algorithms to select one server in a set of storage servers so as to reduce the power consumption of the servers.