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A recent report from Energy Facts Weekly suggests that cloud proponents may be fudging the facts when it comes to claiming just how “green” cloud computing really is.
In an Aug. 22 report, the newsletter quoted an IEEE Proceedings paper, “Green Cloud Computing: Balancing Energy in Processing, Storage and Transport,” as saying “… under some circumstances cloud computing can consume more energy than conventional computing on a local PC.”
A pertinent question to be asked is: What are the “circumstances”? It will require a series of articles to examine more closely the claim that cloud computing is more power efficient and therefore more environmental friendly. Figure 1 shows that as the number of file transfers between the desktop and the cloud increases, the percentage of total power consumed in the transfer process increases.
“For a private cloud storage service,” the reports says, “at a download rate above one download per hour, servers consume 35%, storage consumes less than 7%, and the remaining 58% of total power is consumed in transport. [Emphasis added.] These results suggest that transport dominates total power consumption at high usage levels for public and private cloud storage services.
“The energy consumed in transporting data between users and the cloud is therefore an important consideration when designing an energy efficient cloud storage service. Energy consumption in servers is also an important consideration at high usage levels. The percentage of total power consumed in servers is greater in private cloud computing than that in public cloud computing. In both public and private cloud storage services, the energy consumption of storage hardware is a small percentage of total power consumption at medium and high usage levels. [Emphasis added.]
In other words, for applications where large amounts of data must move between desktop and cloud, more power is required.
