We investigate how to improve Web cluster performance through cooperation protocols for a shared use of the main memories of the server nodes (global caching). Many popular schemes to locate requested documents are based upon locality information sharing (namely, Informed cooperation); we also propose a novel approach for document lookup through a query broadcasting mechanism (namely, On-demand cooperation). Moreover, we consider the Migration and the Handoflmechanisms to retrieve successfully located documents. The four cooperation schemes have been evaluated through synthetic workload driven simulations. The experimental results show that, in a static Web scenario, the On-demand with Handoff scheme performs similarly to the Informed with Handoff scheme, while the On-demand with Migration scheme outperforms the Informed with Migration scheme. On the other hand, in a scenario with some dynamic requests, the On-demand cooperation experiences a significant performance degradation with respect to the Informed cooperation.
By: Marco Emilio Poleggi, Bruno Ciciani, Michele Colajanni’
Published in: RC22482 in 2002
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