SAM Managed Cache and Processing for Clusters in a Worldwide Grid-Enabled System

SAM has been developed within the Computing Division at Fermilab as a versatile, distributed, data management system. One of its many features is its ability to control processing and manage a distributed cache within a cluster of compute servers. Requirements, concepts, and features of this system are described and issues involved in interfacing it to several batch systems are discussed. The system is used within the Dzero experimental collaboration to distribute hundreds of Terabytes of data for processing and analysis around the world. Several hardware configurations deployed at Fermilab are described. Data is currently disseminated using this system to over two dozen sites worldwide, and this number will grow to nearly one hundred in the coming years. The planned design evolution to accommodate this growth is discussed, and the transition of the system to grid standard middleware is described. 1