Impact of elevated temperature on data center operation based on internal and external IT instrumentation

Today's data centers increasingly rely on environmental data collection and analysis to operate the cooling infrastructure as efficiently as possible and to maintain the reliability of IT equipment. This in turn emphasizes the importance of the quality of data collected and its relevance to the overall operation of the data center. This study presents an experiment based analysis and comparison of environmental and power data collection using two different approaches; one uses a discrete sensor network and smart PDUs, and another uses available data from the installed IT equipment (IPMI data). The comparison looks deeply into the effect of both approaches that are adopted to control data center cooling. In addition, the effect that the Supply Air Temperature (SAT) from the Computer Room Air Handler (CRAH) unit had on the IT equipment was investigated in fully sealed Cold Aisle Containment (CAC) with 100% CPU utilization. It can be observed that the difference between the discrete and IPMI inlet temperature of the IT equipment increased as SAT increased due to the IT fans increasing speed in an attempt to get more cooling and the resulting in negative pressure differential build up inside the containment. Furthermore, the authors identified a value of the supply air temperature at which IT equipment started to ramp up for both approaches of data center cooling and control. The novelty of this study may aid data center operators when making the decision of what monitoring or control scheme to use.