Director's column

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CRAY J9: A good deal for single-processor, large-memory jobs

The recent addition of a CRAY J916 supercomputer (paiute) for general use is a significant enhancement to NCAR's computing resources:

• First, this machine makes possible a 20% increase in the GAU pool for both university users and NCAR users.

• Second, it has a 256-megaword memory, so it is better suited to handle jobs that require lots of memory. In fact, SCD encourages anyone who runs single-processor jobs on the CRAY Y-MP8/864 (shavano) that require more than 12 megawords to move those jobs to the J916. (See "Choose paiute over shavano for large-memory jobs" for details).

• Third, GAU charges for memory on the J9 are linear as opposed to quadratic charging on shavano.

• Finally, from 6 p.m. to 6 a.m. daily, priority service is given to jobs that request from 32 to 128 megawords of memory. Such jobs may use one or several processors.

Over the past year, shavano has been heavily loaded; as a result, turnaround for large-memory jobs has been very long. We hope the J9 will provide much better service to large-memory jobs. Further, the ND (near-dedicated) queue on shavano is getting substantial use. So the combination of shavano and the J9 offer:

• Very high performance and favorable charging for multitasked jobs on shavano

• Capability for jobs requiring up to 128 megawords on the J9

I would much appreciate users letting me know (buzbee@ncar.ucar.edu) about any situation where they encounter poor service, especially poor turnaround.