Photo: Image of the Glenn supercomputer

The Ohio Supercomputer Center's IBM Cluster 1350, named "Glenn", features AMD Opteron multi-core technologies. The system offers a peak performance of more than 54 trillion floating point operations per second and a variety of memory and processor configurations. The current Glenn Phase II components were installed and deployed in 2009, while the earlier phase of Glenn – now decommissioned – had been installed and deployed in 2007.

<--break->03/24/2016: Glenn Cluster has been retired. Please see our FAQ page.


The hardware configuration consisted of the following:

  • 436 System x3455 compute nodes
    • Dual socket, quad core 2.5 GHz Opterons
    • 24 GB RAM
    • 393 GB local disk space in /tmp
  • 2 System x3755 login nodes
    • Quad socket quad core 2.4 GHz Opterons
    • 64 GB RAM
  • Voltaire 20 Gbps PCI Express adapters

There were 36 GPU-capable nodes on Glenn, connected to 18 Quadro Plex S4's for a total of 72 CUDA-enabled graphics devices. Each node had access to two Quadro FX 5800-level graphics cards.

  • Each Quadro Plex S4 had these specs:
    • Each Quadro Plex S4 contains 4 Quadro FX 5800 GPUs
    • 240 cores per GPU
    • 4GB Memory per card
  • The 36 compute nodes in Glenn contained:
    • Dual socket, quad core 2.5 GHz Opterons
    • 24 GB RAM
    • 393 GB local disk space in '/tmp'
    • 20Gb/s Infiniband ConnectX host channel adapater (HCA)

How to Connect

To connect to Glenn, ssh to

Batch Specifics

Refer to the documenation for our batch environment to understand how to use PBS on OSC hardware. Some specifics you will need to know to create well-formed batch scripts:

  • All compute nodes on Glenn are 8 cores/processors per node (ppn). Parallel jobs must use ppn=8.
  • If you need more than 24 GB of RAM per node, you will need to run your job on Oakley
  • GPU jobs must request whole nodes (ppn=8) and are allocated two GPUs each.

Using OSC Resources

For more information about how to use OSC resources, please see our guide on batch processing at OSC. For specific information about modules and file storage, please see the Batch Execution Environment page.


Glenn Changelog

Feb 12 2016 - 5:36pm

During the 2/9/16 downtime a change was made to the functionality of qsub affecting all users.

This change requires all user accounts that are a part of multiple projects to specify the project they wish to charge job charges to.  If such a user attempts to submit a job without specifying a project to charge the job charges to the job will not be submitted and an error message will be provided.

Feb 3 2016 - 3:59pm

LAMMPS stable version 7Dec15 has been installed on Glenn, Oakley, and Ruby.  Usage is via the modules lammps-7Dec15 on Glenn and lammps/7Dec15 on Oakley and Ruby.  For information on installation details, such as, available packages, see the output of the respective module help command, e.g.:  module help lammps/7Dec15

May 14 2015 - 4:08pm

The Cambridge Structural Database (CSD) has been moved from Glenn to Oakley, and the latest updates have been installed.  CSD can be run only on  Usage is via the module csd.

Feb 3 2015 - 11:45am

The maximum job size on Glenn has been reduced from 256 nodes (2048 cores) to 128 nodes (1024 cores).  User and group limits are still at 2048 cores total.