1. Dynamic Grid Optimisation TERENA Conference, Lijmerick 5/6/02 A. P. Millar University of Glasgow

2. Dynamic Grid Optimisation TERENA Conference, Lijmerick 5/6/02 Scheduler The Grid Site 1 Site 2Site 3 User

3. Dynamic Grid Optimisation TERENA Conference, Lijmerick 5/6/02 Replica Optimisation Programs running at many different sites use files distributed throughout the Grid. Many programs run. File access patterns collected. Introduce controlled intelligent replication to optimise data access on the Grid. Test optimisation algorithms using simulator: Optor.

4. Dynamic Grid Optimisation TERENA Conference, Lijmerick 5/6/02 Optor – a replica optimiser simulation Simulate prototype particle physics Grid. Input site policies and experiment data files. Introduce replication algorithm: Calculate expected usage. If possible, delete existing file(s) with lower expected usage to allow replication.

5. Dynamic Grid Optimisation TERENA Conference, Lijmerick 5/6/02 Results Introduction of a replication algorithm significantly reduces network traffic and program running times.