  Energy efficiency in a data center is a challenge and has garnered
researchers interest. In this paper we address the energy efficiency issue of a
small scale data center by utilizing Single Board Computer (SBC) based
clusters. A compact design layout is presented to build two clusters using 20
nodes each. Extensive testing was carried out to analyze the performance of
these clusters using popular performance benchmarks for task execution time,
memory/storage utilization, network throughput and energy consumption. Further,
we investigate the cost of operating SBC based clusters by correlating energy
utilization for the execution time of various benchmarks using workloads of
different sizes. Results show that, although the low-cost benefit of a cluster
built with ARM-based SBCs is desirable, these clusters yield low comparable
performance and energy efficiency due to limited onboard capabilities. It is
possible to tweak Hadoop configuration parameters for an ARM-based SBC cluster
to efficiently utilize resources. We present, a discussion on the effectiveness
of the SBC-based clusters as a testbed for inexpensive and green cloud
computing research.
