Opportunities and Advantages

Commodity clusters and Beowulf-class systems bring many advantages to scalable parallel computing, opening new opportunities for users and application domains. Many of these advantages are a consequence of superior price/performance over many other types of system of comparable peak capabilities.

• Capability Scaling. More than even cost effectiveness, a Beowulf system's principle attribute is its scalability. Through the aggregation of commercial off-the-shelf components, ensembles of specific resources deemed critical to a particular mode of operation can be integrated to provide a degree of capability not easily acquired through other means. Perhaps most well known in high-end computing circles is peak performance measured in flops (floating-point operations per second). But another important capability is mass storage, usually through collections of hard disk drives. Commercial database and scientific data-intensive applications both can demand upwards of 100 terabytes of on-line storage. In addition, certain classes of memory intensive applications such as those manipulating enormous matrices of multivariate data can be processed effectively only if sufficient hardware main memory is brought to bear on the problem. We note that while clusters enable aggregation of resources, they do so with limited coupling, both logical and physical, among the constituent elements. This fragmentation within integrated systems can negatively impact performance and ease of use.
• Convergence Architecture. Not anticipated by its originators, commodity clusters and Beowulf-class systems have evolved into what has become the de facto standard for parallel computer structure, having converged on a communitywide system architecture. Commodity clusters employing communitywide message-passing libraries offer a common structure that crosses vendor boundaries and system generations, ensuring software investment longevity and providing customer confidence. Through the evolution of clusters, we have witnessed a true convergence of parallel system architectures, providing a shared framework in which hardware and software suppliers can develop products with the assurance of customer acceptance and application developers can devise advanced user programs with the confidence of continued support from vendors.
• Price/Performance. No doubt the single most widely recognized attribute of Beowulf-class cluster systems is their exceptional cost advantage compared with other parallel computers.For many (but not all) user applications and workloads, Beowulf clusters exhibit a performance-to-cost advantage of as much as an order of magnitude or more compared with massively parallel processors (MPPs) and distributed shared-memory systems of equivalent scale. Today (year of 2002), the cost of Beowulf hardware is approaching one dollar per peak megaflops using consumer-grade computing nodes. The low cost has made Beowulfs ideal for educational platforms, enabling the training in parallel computing principles and practices of many more students than previously possible. More students are now learning parallel programming on Beowulf-class systems than all other types of parallel computer combined.
• Flexibility of Configuration and Upgrade. Depending on their intended user and application base, clusters can be assembled in a wide array of configurations, with very few constraints imposed by commercial vendors. For those systems configured at the final site by the intended administrators and users, a wide choice of components and structures is available, making possible a broad range of systems. Where clusters are to be dedicated to specific workloads or applications, the system structure can be optimized for the required capabilities and capacities that best suit the nature of the problem being computed.
• Technology Tracking. New technologies most rapidly find their way into those products likely to provide the most rapid return: mainstream high-end personal computers and SMP servers. Only after substantial lag time might such components be incorporated into MPPs. Clustering, however, provides an immediate path to integration of the latest technologies, even those that may never be adopted by other forms of high-performance computer systems.
• High Availability. Clusters provide multiple redundant identical resources that, if managed correctly, can provide continued system operation through graceful degradation even as individual components fail.
• Personal Empowerment. Because high-end cluster systems are derived from readily available hardware and software components, installation sites, their system administrators, and users have more control over the structure, elements, operation, and evolution of this system class than over any other system. This sense of control and flexibility has provided a strong attractor to many, especially those in the research community, and has been a significant motivation for many installations.
• Development Cost and Time. The emerging cluster industry is being fueled by the very low cost of development and the short time to product delivery. Based on existing computing and networking products, vendor-supplied commodity clusters can be developed through basic systems integration and engineering, with no component design required. Thus commodity clusters provide vendors with the means to respond rapidly to diverse customer needs, with low cost to first delivery.