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May 8th 2003
Computer Laboratory > Research > Systems Research Group > NetOS > Seminars > May 8th 2003

XenoSearch: resource discovery in the XenoServer Open Platform

David Spence
In the XenoServer project we are building a public infrastructure for wide-area distributed computing, creating a world in which XenoServer execution platforms are scattered across the globe and available for any member of the public. This naturally prompts the question "How does a client find a suitable XenoServer to use"? We anticipate a wide range of job sizes and requirements, not just the large-scale parallel and scientific computation that typifies Grid systems. Furthermore, we view network location as the key driver in selecting XenoServers; perhaps to find one near a particular client, perhaps near a remote machine with which the deployed task will interact, or perhaps within the network to minimize the maximum round trip time between users of a collaborative tool or immersive game. Different jobs will have different needs.

We describe the XenoSearch system for performing expressive resource discovery searches in a distributed environment. We represent server meta-data, such as their locations and facilities, as points in a multi-dimensional space and then express queries as predicates over these points. Each XenoSearch node holds a portion of this space and the key goal of XenoSearch is to direct queries to those nodes containing the meta-data of matching XenoServers. Communication between these XenoSearch nodes is based on the self-organizing Pastry peer-to-peer routing substrate.

Our initial performance evaluation on a wide-area prototype shows that queries are only a factor of 3-5 times longer than basic Pastry routing, while supporting multi-dimensional searches of arbitrary shapes.