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Abstract : |
E#ciency and portability are conflicting objectives for clusterbased network servers that distribute the clients ' requests across the cluster based on the actual content requested. Our work is based on the observation that this e#ciency vs. portability tradeo # has not been fully evaluated in the literature. To fill this gap, in this paper we use modeling and experimentation to study this tradeo # in the context of an interesting class of content-based network servers, the localityconscious servers, under di#erent inter-node communication subsystems. Based on our results, our main conclusion is that portability should be promoted in cluster-based network servers with low processor overhead, given its relatively low cost ( # 16%) in terms of throughput performance. For clusters with high processor overhead communication, e#ciency should be the overriding concern, as the cost of portability can be very high (as high as 107 % on 96 nodes). We also conclude that user-level communication can be useful even for non-scientific applications such as network servers., |
