1. Experiment Support CERN IT Department CH-1211 Geneva 23 Switzerland www.cern.ch/i t DBES Changes in PD2P replication strategy S. Campana (CERN IT/ES) on behalf of ADC

2. CERN IT Department CH-1211 Geneva 23 Switzerland www.cern.ch/i t ES Presentation Title - 2 Current PD2P algorithm For T1s: distributes proportionally with T1 MoU share –This is OK, we do not discuss this today For T2s: same algorithm as job brokering –Send a copy to the place which has higher chance to run a job once the dataset gets there –Weight ~ #CPUS * #Running / # Waiting The current algorithm is optimized for re-brokering –And offloading the T1 Not necessarily it is optimal for an balanced data distribution –The main purpose of PD2P is to replicate popular data for reuse

3. Experiment Support New PD2P algorithm PD2P will use two different algorithm for –Express replica (for quick reuse) –Long Term replica (aimed to balanced data distribution) Express replica –Same algorithm as today. Quick data delivery (use ClosedSites only) Possibility to run promptly a job on the new replica Long Term Replica(s) –Based on size (disk) of the site –Based on performance in Analysis Functional Tests (last month) Presentation title - 3

4. Experiment Support Pd2P and Pre-Placement PD2P and Pre-Placement of data are (almost) orthogonal –PD2P replicates only what has been used – with a minimal delay –Pre-Placement replicates everything The delay can be very short but also very long (congestion after reprocessing for example) ADC would prefer to have only one mechanism for Data Replication: PD2P Presentation title - 4

5. Experiment Support Proposal We leave the situation unchanged for T1s and CERN We keep going with no pre-placement for T2s We increase the number of replicas from PD2P create on first use (and subsequent uses): –One Express Replica at T2s –Two Long Term replicas at T2s PD2P is applied to ADOs, (D)ESDs, NTUP –Both Data and MC –Including what is produced by Group Production Presentation title - 5

6. Experiment Support Monitoring and Docs The PD2P twiki –https://twiki.cern.ch/twiki/bin/viewauth/Atl as/PandaDynamicDataPlacementhttps://twiki.cern.ch/twiki/bin/viewauth/Atl as/PandaDynamicDataPlacement PD2P replication (tables) from Mikhail –http://panda.cern.ch/server/pandamon/q uery?mode=pd2phttp://panda.cern.ch/server/pandamon/q uery?mode=pd2p PD2P logs from Tadashi –http://panda.cern.ch/server/pandamon/q uery?mode=mon&hours=240&name=pa nda.mon.prod&type=pd2phttp://panda.cern.ch/server/pandamon/q uery?mode=mon&hours=240&name=pa nda.mon.prod&type=pd2p Plots from Jarka (will be moved soon, check the twiki above) – http://hpv2.farm.particle.cz/~schovan/pd 2p/pd2p_index.html Presentation title - 6