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Evaluation of Information Service Architectures for Grid. MDS-4 and DHT. Hyerarchical architecure Flat architecture Created for different uses. Focus. Information systems for grid Metadata: resources + users Churn Pragmatical approach. Constraints. Fixed schema Multi-attribute query
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MDS-4 and DHT • Hyerarchical architecure • Flat architecture • Created for different uses
Focus • Information systems for grid • Metadata: resources + users • Churn • Pragmatical approach
Constraints • Fixed schema • Multi-attribute query • Range query • 3 attributes
Index list search • The list is long • The items are geographically dispersed
Hierarchy, MDS4 • Bottleneck for performance • Collected,cached,leased data. • + slow data flow, - old data
Peer-to-peer, Multi Chord • + good for large number of keys • - Churn
Experiment • Size (#nodes, #items) EGEE 250 ,25000 • Schema [CPU,RAM,Diskst] [Group,Role,Capability] • Selectivity on whole range
TTF skewed,TTR fixed, ρ= 0.1, 250 nodes, 120 minutes,CPU data
Conclusions • MDS4, ram, slow, churn<5min, • Much better than Chord on skewed data • Chord multi • Fast • Returns fewer keys
Future • More info available on Dynamic Behaviour of nodes? • Increase size? / Distributed simulation platform • Data models • Query composition: selectivity and bias • How coul make analysis useful to cloud /hibryd solutions? • Any other middleware to compare? • Relevant for DHT ?