The Grid becomes a reality

This week, UK particle physicists have demonstrated the world’s largest, working computing Grid. With over 6,000 computers at 78 sites internationally, the Large Hadron Collider Computing Grid (LCG) is the first permanent, worldwide Grid for doing real science. The UK is a major part of LCG, providing more than 1,000 computers in 12 sites. At the 2004 UK e-Science All Hands Meeting in Nottingham, particle physicists representing a collaboration of 20 UK institutions will explain to biologists, chemists and computer scientists how they reached this milestone.

Particle physics experiments at the Large Hadron Collider (LHC), currently under construction at CERN in Geneva will produce around 15 Petabytes of data each year – 15 million, billion bytes. To deal with this vast volume of data, particle physicists worldwide have been building a computing Grid. By 2007, this Grid will have the equivalent of 100,000 of today’s fastest computers working together to produce a ’virtual supercomputer’, which can be expanded and developed as needed. When the LHC experiments start in 2007, they are expected to reveal new physics processes that were crucial in building the Universe we see today, and shed light on mysteries such as the origin of mass.

Grid computing has been a target for IT developers and scientists for more than five years. It allows scientists to access computer power and data from around the world seamlessly, without needing to know where the computers are. Analysis for particle physics can also be done on conventional supercomputers, but these are expensive and in high demand. Grid computing, in contrast, is constructed from thousands of cheap units that can be increased to meet users’ needs. Like the web before it, the Grid has the potential to impact on everyone’s computing.

GridPP, the UK’s particle physics Grid project, was set up by the Particle Physics and Astronomy Research Council in 2000. On 1 September this year the project reaches its halfway point, with the official end of its first phase and the start of GridPP2. According to Dr Dave Britton, the GridPP project manager, “The first half of the project aimed to create a prototype Grid – which we’ve done very successfully. Having proved that a Grid can work, we’re now focussed on developing a large-scale stable, easy-to-use Grid integrated with other international projects. This will let scientists tackle problems that are much larger than those possible today.”

Dr Jeremy Coles of Rutherford Appleton Laboratory is the GridPP production manager, responsible for making sure the Grid works on a day-to-day basis. He is giving the main GridPP talk in Nottingham, and stresses, “There are a lot of challenges in front of us as we expand our production Grid. In addition to the technical problems involved in providing a well-monitored, stable Grid, we need to address wider issues, in particular encouraging an open sharing of resources between groups of users.”

In Nottingham, conference delegates will be able to see how the particle physics Grid works. GridPP has developed a map that shows computing jobs moving around LCG in real time, as they are distributed to the most suitable sites on the Grid, run their programmes and then return their results home. The map can be seen at http://www.hep.ph.ic.ac.uk/e-science/projects/demo/index.html Dr Dave Colling, from Imperial College, London, whose team built the map, said, “It can be difficult for people who have never seen a Grid working to imagine what it does. Our map is an easy way to see how a Grid can let scientists use resources all over the world, from their desktop. It’s also useful for experts, who can easily see how well the Grid’s working.”

Professor Tony Doyle, leader of GridPP, explained, “This is a great achievement for particle physics and for e-Science. We now have a true international working Grid, running more than 5,000 computing jobs at a time. Our next aim is to scale up the computing power available by a factor of ten, so that we’ll have 10,000 computers in the UK alone, ready for the Large Hadron Collider in 2007”