In the US alone, data centers consumed around $20 billion (200 TWh) yearly electricity in 2016, and this amount doubles itself every five years. Data storage alone is estimated to be responsible for about 25% to 35% of data-center power consumption. Servers in data centers generally include multiple HDDs or SSDs, commonly arranged in a RAID level for better performance, reliability, and availability. In this study, we evaluate HDD and SSD based Linux (md) software RAIDs' impact on the energy consumption of popular servers. We used the Filebench workload generator to emulate three common server workloads: web, file, and mail, and measured the energy consumption of the system using the HOBO power meter. We observed some similarities and some differences in energy consumption characteristics of HDD and SSD RAIDs, and provided our insights for better energy-efficiency. We hope that our observations will shed light on new energy-efficient RAID designs tailored for HDD and SSD RAIDs' specific energy consumption characteristics.
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Ultra-Low Latency SSDs' Impact on Overall Energy Efficiency
Recent technological advancements have enabled a generation of Ultra-Low Latency (ULL) SSDs that blurs the performance gap between primary and secondary storage devices. However, their power consumption characteristics are largely unknown. In addition, ULL performance in a block device is expected to put extra pressure on operating system components, significantly affecting energy efficiency of the entire system. In this work, we empirically study overall energy efficiency using a real ULL storage device, Optane SSD, a power meter, and a wide range of IO workload behaviors. We present a comparative analysis by laying out several critical observations related to idle vs. active behavior, read vs. write behavior, energy proportionality, impact on system software, as well as impact on overall energy efficiency. To the best of our knowledge, this is the first published study of a ULL SSD's impact on the system's overall power consumption, which can hopefully lead to future energy-efficient designs.
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- PAR ID:
- 10171444
- Date Published:
- Journal Name:
- USENIX HotStorage '20
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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