WHEN the first comprehensive report in years to examine energy use by computer servers was published in February 2007, it was greeted with surprise by industry insiders. Jonathan Koomey, a staff scientist at Lawrence Berkeley National Laboratory in California, found that worldwide power consumption by servers had doubled between 2000 and 2005. "Everyone thought CO2 emissions were a problem for transportation and big energy," says Bill St Arnaud of Canarie, Canada's internet development organisation in Ottawa, Ontario.
Since then a raft of studies have highlighted the rocketing energy demands made by computers . One of them, a report from UK-based Global Action Plan, puts carbon dioxide emissions from information and communications technology on the same level as that of the aviation industry - 2 per cent of global emissions. As it turns out, many of the tech titans were already on the case. A week after Koomey's report came out, industry giants including Microsoft, Intel, Dell, IBM and Sun Microsystems forged a collaboration known as the Green Grid . Their aim was to attack a host of hardware and software inefficiencies in data centres - farms of servers that store and retrieve online information. They regard the problem as so large that collaboration is essential. "There was a recognition that there was a problem in energy efficiency in data centres that was too vast to be solved by any one company," says Green Grid director Lawrence Lamers of software company VMware in Palo Alto, California, which makes the so-called virtualisation software regarded by many companies as a prime way to save energy. At about the same time, energy consultancies identified the problems associated with and began to float ideas for possible solutions. These included solar and hydroelectric power, and converting alternating current from the mains to direct current (DC) just once in the data centre, instead of repeating the process many times at different servers, as happens today (New Scientist , 15 December 2006, p 24). Although some data centres, including Google's, use some renewable energy, these measures are unlikely to be enough. DC conversion requires significant changes to infrastructure, and companies are looking for technologies they can implement immediately. Green Grid director, Mark Monroe of Sun Microsystems, points out that another major factor driving companies to reduce energy consumption is concern about supply. "We are trying to make data centres efficient enough so that they don't outstrip energy availability," he says. The need for greener computing is huge. Whenever you download music, send an email, access medical records, or make a credit card transaction, the actions are processed in a data centre. "Three years ago, YouTube didn't exist," Lamers says. "Now there are hundreds of millions of videos being downloaded by millions of users. Yahoo is giving away free email with unlimited storage. Do you know how many servers are required for millions of users to store gazillions of emails?" The Green Grid's biggest achievement to date is a first attempt at finding a standardised way to measure the efficiency of data centres. This would allow customers to compare centres and companies to identify the worst offenders and upgrade them. Some individual member companies are already moving beyond this. Take IBM, which provides data storage and number crunching services for the financial, pharmaceutical and retail sectors. In May it pledged to invest $1 billion annually in a project called Big Green , which aims to double computing capacity at IBM's data centres without increasing energy consumption. "This is absolutely one of IBM's key plays right now," says Chris Scott, head of IBM data centre services for north-east Europe. "It's saving us money, it's giving us growth capacity, and it's the right thing to do for the environment." Like many members of the Green Grid, IBM is making virtualisation software a central part of its greening strategy. First used in the 1960s as a way to divide large mainframe computers into smaller parts, each capable of performing its own small task simultaneously, virtualisation is now seen as the low-hanging fruit in data centres' green transition. Virtualisation software creates multiple "virtual machines" (VMs), which are layers of software that emulate a particular type of hardware. Each VM sits between the actual hardware and a specific software application, and looks like hardware to the application. Running applications on VMs instead of directly on the hardware means the separate applications can't interfere with each other, and if one application crashes, it doesn't affect the others. When servers replaced mainframes, there was no need to partition them with virtualisation as each server was built to execute one application. But the processing power of servers has now increased to the point that running only one program per server typically means using less than 15 per cent of its capacity. The obvious answer is to run several applications on a single server, as with mainframes. In 2001, VMware introduced the first virtualisation software written specifically for the type of servers widely used in data centres. "It makes the difference between buying 10 servers or buying one," says Bogomil Balkansky at VMware. "Customers are able to save 70 to 80 per cent on energy use. It's the best way to immediately and dramatically reduce power consumption in the data centre." In August, as a result, IBM was able to replace 3900 of its Intel servers with 33 larger ones with more efficient (New Scientist , 10 March, p 26). "That is an 80 per cent reduction in energy consumption and an 85 per cent reduction in space," Scott says. Virtualisation and multicore chips aren't the only ways to green data centres. Other Green Grid members believe that an important contribution is improving the efficiency of applications themselves. Arjan van de Ven, a software engineer at chip maker Intel, is leading an initiative called Lesswatts.org to make the popular Linux open-source operating system more efficient. Many companies, including Google, run their data centres on Linux. By tweaking existing Linux code, Van de Ven and his team were able to detect which programs were behaving badly. This revealed that Linux was performing a lot of small, senseless tasks. One example was "ondemand", a program designed to save power by checking the computer's central processing unit (CPU) for activity and reducing power consumption when activity was low. The researchers discovered that it was contacting the CPU several hundred times a second, which was enough to make the CPU more active than it would have been without ondemand running at all. "Here we have a piece of software designed to save you power that is actually wasting power," Van de Ven says. Because Linux is open-source they were able to rewrite the program so that it checks CPU activity less often. The team also found energy-wasters in a version of Linux that runs on personal computers. These included a program that checks the email inbox 100 times per second even though the inbox only asks the server if there is new email every 5 minutes; a clock that updates every second even though it displays the time in minutes; and a program that asks the hardware 10 times a second if the volume of a speaker has changed even though another program is already set up to tell the hardware when speaker volume changes. "These sound like little things, but if you have 40 programs that do this, they add up," says Van de Ven. The team has made its upgrades available via various open-source software mailing lists over the last year, and two versions of Linux for laptops have incorporated them. Along with Google and the conservation group WWF, Intel is also a member of the Climate Savers Computing Initiative , a collaboration Intel helped to found in June 2007. Rather than focusing on the data centre as a whole, the CSCI is looking at how to improve the efficiency of individual servers. One strategy that Google has already implemented on some computers is eliminating voltage conversions within individual computers. In the future, CSCI directors imagine having personal computers that can adjust their energy consumption in proportion to their workload. Today's computers tend to use the same amount of energy, no matter what they are doing. Bill Weihl of Google, who is also co-chair of the CSCI, is optimistic that its efforts and that of the Green Grid will reduce the amount of energy data centres and personal computers use. Whether it is enough to offset the predicted growth in computer use over the next 20 years "is hard to predict", he says. -- sanjay Prasad, Home Phone 02228122688 Sanjay To unsubscribe send a message to [EMAIL PROTECTED] with the subject unsubscribe. To change your subscription to digest mode or make any other changes, please visit the list home page at http://accessindia.org.in/mailman/listinfo/accessindia_accessindia.org.in
