Case study: Swinburne University
The Centre for Astrophysics and Supercomputing at Swinburne University has around 300 Intel CPUs in a Beowulf cluster, including 90 dual Xeon 2.2GHz systems connected via gigabit Ethernet.
Thirty more dual Xeons are located at the Parkes radio telescope, where they are primarily used for real-time data reduction before observations are stored on disk. Even though there is no high-speed link between Melbourne and Parkes, these systems can be used as part of the cluster when they would otherwise be idle.
The cluster is being used for cosmological models involving N-body and hydrodynamic simulations. Another application is engineering simulations of the Square Kilometre Arrayâ€"a proposed international project to build a radio telescope with an effective collecting area of one square kilometre.
Around 20 percent of the computing resource is used outside the Centre, says acting director Professor Brad Gibson. In the research sphere, applications include brain simulation and molecular modelling. There are also public outreach projects such as the Virtual Milky Way, and commercial ventures such as rendering 3D VR movies for museums and observatories.
The Centre has plenty of experience with cluster computing, having previously run an Alpha cluster, followed by a smaller Beowulf cluster of 32 Pentium III CPUs. -The code ran very well, [and was] very fast," says Gibson, hence the new system.
The current cluster was funded by Swinburne, and as part of the Square Kilometre Array project by the Victorian and Commonwealth governments, with help from Dell and Intel.
-The bottom line for us . . . is [the] price-performance ratio," says Gibson. -This is the best compromise and gives us great performance," he adds. The cluster gets into the teraflop range, and when the planned high-speed interconnections are installed, he expects the system to be around the 40th fastest in the world.
The cost of those interconnections is an issue. When you are linking over 100 nodes, -the price sure does go up quickly," says Gibson, even though they are readily affordable for smaller numbers.
While the cluster's primary operating system is Linux, the rendering jobs run on Windows-based software. -It may take an hour or two, but you can bring the nodes up under Windows," says Gibson, which would not be possible with a traditional supercomputer.
One of the newest additions is a quad Itanium II system, which combines 64-bit CPUs and the ability to address 64GB of memory per node. This will be especially useful for cosmological simulations, but the Centre has not ported any of its code to the new system. Gibson says the extra speed could reduce processing times from weeks to days, and the obvious upgrade path for the next few years is to this type of processor.
The code used by the Centre could be ported to any type of computer, but they have been tuned for distributed memory systems like the Beowulf cluster. The tweaking process will continue: -There's no reason why we couldn't improve things 30 to 40 percent," he says, suggesting that it is cheaper to spend a few months working on the code than it would be to get the extra speed via Rolls Royce hardware.
In recent years, the focus for clustering has moved to using large numbers of commodity PCs.
Distributed computing: an executive summary
- Grid computing enables the integration of processing power, data storage and presentation across organisational and (potentially) geographical boundaries.
- Grid computing is based on open standards, including Web Services.
- Some vendors see grid technology as a way to deliver computing as a utility, with a similar model to electricity and water supplies.
- Clustering provides a way to bring large numbers of low-cost CPUs to bear on large-scale problems.
- Not all computationally intensive problems are suited to being solved on a cluster.
- Distributed technologies may provide a way of harnessing spare capacity within an organisation.
- Companies are already delivering systems that take advantage of clustered hardware.
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