Figure 5 - uploaded by Anand Natrajan
Content may be subject to copyright.
Context in source publication
Similar publications
Citations
Applications enabled by the increasing availability of high-performance networks require the ability to share resources that are spread over complex, large-scale, heterogeneous, distributed environments spanning multiple administrative domains. We call this the wide-area computing problem. We argue that the right way to solve this problem is to build an operating system for the network that can abstract over a complex set of resources and provide high-level means for sharing and managing them. We describe the design of one such wide-area operating system: Legion. Through discussion of application examples, we demonstrate the attractive features of Legion approach to constructing a wide-area operating system using distributed object components.
Grid computing has been a hot topic for a decade. Several systems have been developed. Despite almost a decade of research and tens of millions of dollars spent, uptake of grid technology has been slow. Most deployed grids are based on a toolkit approach that requires significant software modification or development. An operating system technique used for over 30 years has been to reduce application complexity by providing transparency, e.g. file systems mask details of devices, virtual machines mask finite memory, etc. It has been argued that providing transparency in a grid environment is too costly in terms of performance. This paper examines that question in the context of data grids by measuring the performance of a commercially available data grid product - the Avaki Data Grid (ADG). We present the architecture of the ADG, describe our experimental setup, and provide performance results, comparing the ADG to a native NFS V3 implementation for both local and wide area access cases. The results were mixed, though encouraging. For single client local file operations, native NFS outperformed the ADG by 15% to 45% for smaller files, though for files larger than 32 MB ADG outperformed native NFS.
Legion was the first integrated grid middleware architected from first principles to address the complexity of grid environments. Just as a traditional operating system provides an abstract interface to the underlying physical resources of a machine, Legion was designed to provide a powerful virtual machine interface layered over the distributed, heterogeneous, autonomous, and fault-prone physical and logical resources that constitute a grid. We believe that without a solid, integrated, operating system-like grid middleware, grids will fail to cross the chasm from bleeding-edge supercomputing users to more mainstream computing. This work provides an overview of the architectural principles that drove Legion, a high-level description of the system with complete references to more detailed explanations, and the history of Legion from first inception in August 1993 through commercialization. We present a number of important lessons, both technical and sociological, learned during the course of developing and deploying Legion.
