1. PDSF Computing model Thomas Davis ASG/NERSC, LBNL LCCWS

2. Contents " Why PDSF at a supercomputing center? " Short history of PDSF " What does PDSF do? " How do I get access to PDSF? " Hardware " Software

3. Why PDSF at a Supercomputing Center? " Sharing of resources – 24x7x365 glass house. – Can leverage some vendors expertise. – Access to expertise in data management, networking, and other important services. – Large cluster could be the next HPC system; so PDSF provides production experience with clusters.

4. Short history of PDSF " Came from SSC, crated and moved to Livermore. " No new hardware, software for close to 8 years. " Life support applied when NERSC moved to Berkeley from Livermore in 1997 " Has picked up experimental support ever since, with what appears to be a 1000% growth rate.

5. How do I get PDSF access? " Buy in service model. Clients pay for a fixed slices of CPU time/disk space. – Over time, as cluster grows, the amount of disk space and cpu time drops. Moore's law is in effect. " Client has no direct ownership of cluster. PDSF admins have the right to move resources around when needed. " Client can get more CPU power than what they buy – if no one else is using CPU's in cluster, then resources are available to other users. – LSF Fairshare is used to arbitrate between clients. " Equipment is retired based on Moore's law, and warranties.

6. PDSF Hardware model " CPU power is always moving. – We expect to retire any Intel based system after 3 years. " Disk size is climbing even faster; new drives replace old disks, increasing volume size and performance. " Memory constraints can also force retirement of systems.

7. Hardware, Continued. " New hardware is always bought as late as possible. " CPU speeds are based on the knee of the curve; 2x650mhz machines are better than 1x1Ghz machine. " Memory is also bought based on size; always buy largest dimm's when possible.

8. Software model. " Platform LSF is used for batch queuing. – Fought for better pricing.. but Platform still wants lots of money. " Redhat 6.1 is software base. – Only updated when needed; many experiments can't change. " Control of software is vigorous; because PDSF has many experiments, any software changes are controlled. " Opensource is preferred, but properiety software is acceptable.