After eight years of service, Sequoia has been felled. Once the most powerful publicly ranked supercomputer in the world, Sequoia – hosted by Lawrence Livermore National Laboratory (LLNL) – has been decommissioned to make room for LLNL’s new supercomputer: the exascale “El Capitan” system. The system was decommissioned on January 31st and will be dismantled over the “first few months of 2020.”
Sequoia was a water-cooled IBM BlueGene/Q system primarily comprised of 98,304 compute nodes spread across 96 racks, along with 55 PB of disk storage. Each node held 16 PowerPC A2 CPUs with a 1.6 GHz clock and 16 GB of memory (for a total of around 1.6 PB). Nodes used a 5D Torus interconnect. At its launch in 2012, Sequoia delivered 16.3 Linpack petaflops out of 20.1 theoretical petaflops of performance. In 2013, an optimized benchmarking run increased its Linpack score to 17.2 petaflops.
Shortly after Sequoia was fully deployed at LLNL, it overtook the top spot on the June 2012 Top500 list. That same year, Oak Ridge National Laboratory (ORNL) took the title from Sequoia with Titan, which itself was decommissioned last summer. (See ORNL article on how Titan was recycled.) Sequoia remained a strong contender on the Top500 until its decommissioning: it remained in the top 10 as recently as 2018, and as of the November 2019 list, it still placed 12th.
While Sequoia’s missions revolved around numerical simulations of nuclear weapons performance and general weapon science, its particular strengths lay in the processing of large datasets for all kinds of simulations. Over the course of its eight years of operation, Sequoia simulated the behavior of galaxies, thermonuclear fusion, supersonic jet engines and much more. It even enabled a computational fluid dynamics simulation that won a Gordon Bell Prize.
“What a run! The Sequoia #supercomputer gave us 8 years of predictive #simulation capabilities in service to national security,” LLNL tweeted. “But we need the floor space for El Capitan.”
El Capitan, a Cray Shasta-based system that will be delivered in 2022 and reach full operation in 2023, will be one of the first exascale computers in the United States (following Aurora and Frontier in late 2021), and the first for LLNL and the National Nuclear Security Administration (NNSA). LLNL expects that El Capitan will run nuclear security applications more than 50 times faster than Sequoia.
“The Department of Energy is the world leader in supercomputing and El Capitan is a critical addition to our next-generation systems,” said (former) U.S. Energy Secretary Rick Perry when El Capitan was announced. “El Capitan’s advanced capabilities for modeling, simulation and artificial intelligence will help push America’s competitive edge in energy and national security, allow us to ask tougher questions, solve greater challenges and develop better solutions for generations to come.”