Sierra, Livermore’s next advanced technology high performance computing system, is joining LLNL’s lineup of supercomputers in 2018. The new system will provide computational resources that are essential for nuclear weapon scientists to fulfill the National Nuclear Security Administration’s stockpile stewardship mission through simulation in lieu of underground testing. Advanced Simulation and Computing (ASC) Program scientists and engineers will use Sierra to assess the performance of nuclear weapon systems as well as nuclear weapon science and engineering calculations. These calculations are necessary to understand key issues of physics, the knowledge of which later makes its way into the integrated design codes. This work on Sierra has important implications for other global and national challenges such as nonproliferation and counterterrorism.

For Sierra's installation, the CORAL partnership (Collaboration of Oak Ridge, Argonne, and Livermore) was formed to procure high performance computers from multiple vendors. IBM was selected as the vendor for LLNL. The IBM-built Sierra supercomputer is projected to provide four to six times the sustained performance and five to seven times the workload performance of Sequoia, with a 125 petaFLOP/s peak. At approximately 11 megawatts, Sierra will also be about five times more power efficient than Sequoia. By combining two types of processor chip—IBM’s Power 9 processors and NVIDIA’s Volta graphics processing units—Sierra is designed for more efficient overall operations and is expected to be a promising architecture for extreme-scale computing.

System Details (subject to change on final install) Sierra Lassen (aka uSierra) RZAnsel
Nodes 4,320 684 54
POWER9 processors per node 2 2 2
GV100 (Volta) GPUs per node 4 4 4
Node Peak (tFLOP/s) 29.1 29.1 29.1
System Peak (pFLOP/s) 125 19.9 1.57
Node Memory (GiB) 320 320 320
System Memory (PiB) 1.29 0.209 0.017
Interconnect 2x IB EDR 2x IB EDR 2x IB EDR
Off-Node Aggregate b/w (GB/s) 45.5 45.5 45.5
Compute racks 240 38 3
Network and Infrastructure racks 13 4 .5
Storage Racks 24 4 .5
Total racks 277 46 4
Peak Power (MW) ~12 ~1.8 0.14

Our CTO's Sierra Overview PowerPoint provides even more details. Or, view our latest LLNL press release and video.