1. 14 Aug 08DOE Review John Huth ATLAS Computing at Harvard John Huth

2. 14 Aug 08DOE Review John Huth ATLAS Computing at Harvard Two functions –Supply computing power (storage and CPU) for Harvard investigators to support analysis and simulation –Act as a Tier 2 facility, jointly with BU (Northeast Tier 2 – NET2). Recent addition of substantial local resources for computing, connected to the Open Science Grid

3. 14 Aug 08DOE Review John Huth The ATLAS computing model uses a tiered system in order to enable all members speedy access to all reconstructed data needed for analysis and raw data needed for monitoring, calibration, and alignment ATLAS Computing Model Tier-0 at CERN Archives and distributes RAW data Provides first pass processing Restricted to central production group ~10 Tier-1 Facilities Stores select RAW data, stores derived data, and performs processing on RAW data Restricted to working group managers Regional Tier-2 Facilities Resources for local research, such as analysis, simulation, and calibration Open to all members of the collaboration Local Tier-3 Facilities Typically clusters housed at a university or lab Allows fast analysis of derived datasets Typically open only to local members RAW data from ATLAS Simulated data RAW data Derived data Derived data

4. 14 Aug 08DOE Review John Huth Computing Requirements

5. 14 Aug 08DOE Review John Huth Integrating computing and storage resources from more than 50 sites, OSG is a U.S. distributed computing infrastructure designed for large-scale scientific research OSG provides the software framework, middleware, and oversight for more than 35 Virtual Organizations (VOs), which provide local resources and user services OSG is funded and supported by the NSF and DOE Open Science Grid

6. 14 Aug 08DOE Review John Huth Harvard and Scientific Computing A recent and dramatic increase in support for scientific computing at Harvard –Hardware, facilities and personnel Commitment to a major scientific computing center along Oxford Street –Currently rental space at 1 Summer Street Facility –Dedicated support for high-end computing supplied by University

7. 14 Aug 08DOE Review John Huth Harvard’s Role in ATLAS Computing Model BNL Tier-1 CPU: 4900 kSi2K Disk: 2000 TB Tape: 1000 TB CERN Tier-0 CPU: 4480 kSi2K Disk: 330 TB Tape: 1620 TB BU ATLAS Cluster CPU: 700 kSi2K Disk: 236 TB Tape: 0 TB Harvard University Odyssey Cluster CPU: 5600 kSi2K Disk: 300 TB Tape: 0 TB Northeast Tier-2 Overall flow of data into NET2

8. 14 Aug 08DOE Review John Huth FAS Computing

9. 14 Aug 08DOE Review John Huth 15th April 2008MIT Network Meeting Odyssey physical installation at 1 Summer Street

10. 14 Aug 08DOE Review John Huth 15th April 2008MIT Network Meeting Capabilities of Odyssey General purpose Intel x86_64 4096 CPU cores (9,543GHz) 16TB DRAM Infiniband fully non blocking ~ 31.7 TFlop @ 84% efficiency

11. 14 Aug 08DOE Review John Huth FAS Cluster configuration - 1

12. 14 Aug 08DOE Review John Huth Odyssey Performance Tests of the Odyssey cluster showed that a sustained rate up to 600 jobs could be handled under even heavy concurrent loads. These were mainly simulation jobs with light I/O.

13. 14 Aug 08DOE Review John Huth Computing Capabilities Based on the CPU ratings, the Harvard cluster has as much aggregate CPU power as all other US ATLAS Tier 2’s combined. Based on concurrent usage (other applications), it is likely that we can at least triple the CPU power available for the NET2 with Odyssey online. Available for Harvard ATLAS as priority, a huge resource for analysis and data storage. –Example of “leverage” envisaged for Tier 2’s