Information Technology Reference
In-Depth Information
estimates that the global demand for electricity from data centers was around 330bn
kWh in 2007 (almost the same amount of electricity consumed by UK [3]). This
demand in power consumption demand is projected to more than triple by 2020 (more
than 1000bn kWh). According to some estimates [3],[4], the power consumption of
the data centers in the US in 2006 was 1.5% of the total energy consumed at a cost of
more than $4.5B.
Derive electricity
consumption
Forecast electricity
consumption
Billion kWh 2007
Billion kWh 2020
Data Centers
330
1012
Telecoms
293
951
Total Cloud
623
1963
Fig. 1.
Power consumption of data centers, Source: Greenpeace, [2]
The power consumption inside the data center is distributed in the following way:
the servers consume around 40% of the total IT power, storage up to 37% and the
network devices consume around 23% of the total IT power [5]. And as the total
power consumption of IT devices in the data centers continues to increase rapidly, so
does the power consumption of the HVAC equipment (Heating-Ventilation and Air-
Conditioning) to keep steady the temperature of the data center site. Therefore, the
reduction in the power consumption of the network devices has a significant impact
on the overall power consumption of the data center site. According to a study from
Berk-Tek, saving 1W from the IT equipment results in cumulative saving of about
2.84W in total power consumption due to the reduced power consumption of the
cooling systems [6]. Therefore, a reduction on the power consumption of the
interconnection network will have a major impact on the overall power consumption
of the data center.
The power consumption of the data centers has also a major impact on the
environment. In 2007, data centers accounted for 14% of the total ICT greenhouse
gases (GHG) emissions (ICT sector is responsible for 2% of global GHG emissions),
and it is expected to grow up to 18% by 2020 [2]. The global data center footprint in
greenhouse gases emissions was 116 Metric Tonne Carbon Dioxide (MtCO2e) in
2007 and this is expected to more than double by 2020 to 257 MtCO2e, making it the
fastest-growing contributor to the ICT sector's carbon footprint.
Therefore, more energy efficient servers are required for the emerging cloud
computing applications. In [7],[8], a performance evaluation study has been presented
between high performance server cores (e.g. Intel Xeon processors) with low power
general purpose cores (e.g. Intel Atom processors). The comparison has shown that
low power general purpose cores can achieve better energy efficiency in the domain
of web search applications. One of the first companies that adopted the used of low
power general purpose processors was SeaMicro [9]. SeaMicro introduced in 2011 a
new version of servers that packed 768 Intel Atom cores into a 10U chassis.
According to the company the Atom-based data center could achieve ΒΌ the power and
1/6 the space of the commodity volume servers. Another company, Calxeda Inc. has
recently presented a server based on the ARM cores called Server-on-a-Chip (SoC).
