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OPINION
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For the last few decades we have witnessed the relentless , exponential growth of the Internet . Alongside this there have been rapid increases in the number of connections , their bit rates and throughput . At the same time , the negative environmental impact of the ICT sector has escalated just as dramatically , and what ’ s more , it ’ s now highly visible .
It is estimated that ICT currently consumes around 2 per cent of worldwide electricity production . Alarmingly this is predicted to grow to 10 per cent of global consumption by 2020 and it goes without saying that this will come with an associated increase in the global ICT carbondioxide footprint . All of this is not lost on an increasingly aware group of professional consumers of ICT services : they have started to take note and seriously consider the environmental impact when making their purchasing decisions and this is the reason why sustainability has become a substantial challenge for the future shape and operation of data centres .
Over the last few years there has been a lot of effective hard work and it has resulted in substantial and important improvements in increasing the power efficiency metrics . Yet despite all of this effort , the growth in cloud consumption continues to outpace improvements in energy efficiency , meaning that there is no progress .
Power continues to be the number one constraint in the operation of any data centre and this is why data centre operators ( DCOs ) have responded with a steady rise in power that is available at building , floor , row , and rack level . For instance , the maximum power limit per rack has climbed steadily through 6 , 8 , 10 , to 12kW and there are instances as high as 16kW in operation today . Clearly , delivering more power to data centres and the racks that they host will not solve the associated environmental impact and may increase the negative perception . What ’ s more , one could argue that this short term reaction only serves to mask the problem and ultimately sends us in the wrong direction .
Deriving more from less Sometimes it can be argued that the best way of improving power dissipation is to tackle overall efficiency and recent industry efforts have centred on reducing the amount of processing required as data moves into and out of a piece of equipment within a data centre . Rather than simply squeezing as many Watts out of each server as possible , trying instead to remove redundant and unnecessary layers and levels of processing will potentially yield a much greater improvement .
As just one of many examples , the IEEE has been working on 25Gbit / s and 50Gbit / s variants of Ethernet , in an effort to make the flow of data from servers , through switches and routers and then across transport links , as straightforward as possible . The general thinking here is that if all of the Ethernet speeds are even integer multiples of one another ( i . e . 25 , 50 , 100 , 200 , 400 ) then the underlying multiplexing , aggregation and scheduling of packets of various sizes will become much more efficient . Early testing seems to support this .
Mathematics to the rescue Another way of getting more from less is to pack more information into the same number of electrical traces , patch cables and fibre optics . The advance from 10 Gigabit Ethernet to as much as 400 Gigabit Ethernet was enabled by the move to higher order modulation techniques that carry
“ The best way of improving power dissipation is to tackle overall efficiency ”
more information per bit . While similar techniques have been a staple of radio frequency and wireless technologies for decades , only recently have digital signal processors ( DSP ) and photonic integrated circuits ( PIC ) reached the point where complex signal modulation is possible . These techniques allow as many as 64 states to be encoded onto a single data signal that used to contain only 2 : on and off .
Not just green but also sustainable The energy consumption of a data centre and its related cost , as well as the associated CO2 footprint are not the only areas that DCOs need to consider . Aspects like logistics , resource management and the supply chain must also be taken into account . In other words , it is the overall sustainability of the data centre that should be the focus . This leads to the concept of the Circular Economy which is now being heavily pushed in both the EU and the US . Circular Economy aims to reduce raw-material intake as well as of the resulting waste . Basic ideas of the concept are extended product lifetime , including parts re-use and product second-life .
Optimised recycling is another central tenant of the Circular Economy and this means getting close to 100 per cent recovery of all valuable material from waste electrical and electronic equipment . And it ’ s essential to recover this in the best possible quality , thus avoiding down cycling which only recovers poor-grade material and produces less functionality . To achieve this kind of optimised recycling , serious thought needs to be given to easing the process of disassembly through product eco-design and the avoidance of problematic materials and material composites in all processes .
Then there ’ s the issue of how DCOs assess their environmental impact . Rather than just measuring the energy of the servers , the total energy that the data centre consumes needs to be recorded and considered . For example , the power consumed by workers traveling to and from the data centre , the energy used in deliveries to and from the data centre , energy consumed to dispose of or recycle DC waste , etc . And for a truly holistic sustainability approach the impact of all the suppliers also needs to be measured and accounted for .
Hope for the Future Greening the data centre will take more than shaving off a watt here and there . It ’ s going to require an all-out multipronged approach that considers every angle honestly and without compromise . It will need to consider delivering more power at lower price points , removing layers of processing , making existing channels carry much more information for the same unit of power and looking at energy consumed during the entire lifecycle of direct and indirect data centre operations .
It is only by accounting for everything between breaking the ground to decommissioning the data centre , including all of the sustainability steps in between , that DCOs will be able to look the world in eye . n
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