NERSCPowering Scientific Discovery Since 1974



Current Status: Retired

Hopper was retired on Dec 15, 2015. Login nodes and scratch file systems were available until noon Dec 22, 2015.

Hopper was NERSC's first petaflop system, a Cray XE6, with a peak performance of 1.28 Petaflops/sec, 153,216 compute cores, 212 Terabytes of memory, and 2 Petabytes of disk. Hopper placed number 5 on the November 2010 Top500 Supercomputer list.

Updates and Status

Find information on known problems, open issues, and recent announcements. Read More »

Getting Started

How to get running on Hopper for first-time users. Read More »


NERSC's Cray XE6, Hopper, has a peak performance of 1.28 Petaflops/sec, 153,216 processors cores for running scientific applications, 212 TB of memory, and 2 Petabytes of online disk storage. Read More »


Find information on how to compile your application, use MPI and OpenMP optimally, and use Cray's scientific libraries. Read More »

Running Jobs

Learn how to submit a job to the queues and use the 'aprun' job launch command, monitor your job in the queue and job exit status. Also find information on OpenMP and MPI runtime settings as well as general application tuning options. Read More »

File Storage and I/O

The Hopper system has 5 different file systems mounted which provide different levels of disk storage, I/O performance and file permanence. Find information on I/O optimization, disk quotas and purging. Read More »

Software and Tools

The table below shows the software installed on Hopper that is managed by modules. Read More »

Debugging and Profiling

Information on how to use debugging and profiling tools on the Hopper system including DDT, Totalview, IPM, and Craypat. Read More »

Performance and Optimization

Hopper performance graphs, benchmarking results and compiler comparisons. Read More »

Cray XE Documentation

Documentation from Cray, Inc. Read More »

Cluster Compatibility Mode

Cluster Compatibility Mode (CCM) allows users to run standard ISV applications and other applications that need to use sockets on the Hopper system. Read More »