|Active||Scheduled delivery in fiscal 2018|
|Operators||National Nuclear Security Administration|
|Location||Lawrence Livermore National Laboratory|
|Architecture||IBM POWER9 CPUs|
Nvidia Tesla V100 GPUs
Mellanox EDR InfiniBand
|Speed||125 petaflops (peak)|
|Purpose||Nuclear weapon simulations|
Sierra or ATS-2 is a supercomputer built for the Lawrence Livermore National Laboratory for use by the National Nuclear Security Administration as the second Advanced Technology System. It is primarily used for predictive applications in stockpile stewardship, helping to assure the safety, reliability and effectiveness of the United States' nuclear weapons.
Sierra is very similar in architecture to the Summit supercomputer built for the Oak Ridge National Laboratory. The Sierra system uses IBM POWER9 CPUs in conjunction with Nvidia Tesla V100 GPUs. The nodes in Sierra are Witherspoon S922LC OpenPOWER servers with two GPUs per CPU and four GPUs per node. These nodes are connected with EDR InfiniBand.
- Trinity (supercomputer) – ATS-1, the first Advanced Technology System
- Summit (supercomputer) – a similar POWER9 NVLink system
- Morgan, Timothy Prickett (2017-10-05). "The Clever Machinations Of Livermore's Sierra Supercomputer". The Next Platform.
- "Installation of Sierra Supercomputer Steams Along at LLNL". HPCwire. 2017-11-20.
- Smith, Ryan (2014-11-17). "NVIDIA Volta, IBM POWER9 Land Contracts For New US Government Supercomputers". AnandTech.
- "The New Supercomputer Behind the US Nuclear Arsenal". Verge Science. November 20, 2018 – via YouTube.