Abstract
Reducing data center (DC) power consumption is one of green Information and Communication Technology (ICT) challenges, which can be realised through improvement of DC energy-efficiency. To accomplish this improvement, each component of DC including those of power supply system such as uninterruptible power supplies (UPSs), has to operate at its maximum power efficiency. Since the broadly accepted concept based on server consolidation approach demonstrates significant DC power saving at the level of server racks, the contribution of constantly active UPSs to the overall DC power inefficiency become non-negligible. It is shown that a possible technique for reducing UPS power inefficiency in DCs can be based on dynamic merging of UPS activity state with server consolidation, where the neighbouring connectivity between one UPSs and two neighbour server racks have been established on the backup power supply paths. In this paper enhancement of neighbouring connectivity concept based on a new approach for establishing connectivity between UPSs and server racks on DC backup power delivery paths are introduced. More specifically, the algorithm which enables serial connectivity of active UPSs with DC server racks during merged UPS and server consolidation process is proposed. Through the extensive simulations of real DC having a large number of rack servers and UPSs, the proposed concept based on serial connectivity has been tested. Results show that proposed concept improves the energy-efficiency of DC when compared with neighbouring connectivity approach or existing legacy DC power supply approach lacking any UPS consolidation. Proposed concept can be used in practice as a solution which can reduce the impact of power consumption inefficiency of UPSs as main DC power supply elements.