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Terra:Computing Environment

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Computing Environment

Introduction

Terra is using the CentOS 7 Linux distribution on all nodes. The global file systems (accessible to all nodes) are organized by IBM's General Parallel File System (GPFS). These are /home and /scratch. Both are hosted on the 2PB (raw) disk space provided by the IBM GSS26 appliance.

The batch system, although a 'very important part of the computing environment, is covered in a separate section of its own. More information on the batch system can be found on the Batch Processing page.

Login

The default shell for Terra (all nodes) is bash. Its environment is defined in the startup file, .bash_profile. It is read and executed when you login, and it resides in your home directory.

Each of the three login nodes can be accessed with ssh to terra.tamu.edu. To access a specific login node, you would need to use the specific name to ssh. To access Terra, use the following command from your local machine:

[user1@localhost ~]$ ssh [NetID]@terra.tamu.edu

The use of the login nodes is for small-to-medium code development and processing. The most important processing limits here are:

  • CPU time - ONE HOUR per login session.
  • Cores for Concurrent Use - EIGHT CORES per login session, on the same node or (cumulatively) across all login nodes.

ANYONE found violating these limits WILL have their processes killed WITHOUT WARNING. Repeated violation of these limits WILL result in account suspension.

More information about the hardware of each of the login nodes can be found on the Hardware Summary page.

File Space

Immediately upon logging in to Terra, the following message about the status of your disk space use greets you:

Your current disk quotas are:
Disk       Disk Usage      Limit    File Usage      Limit
/home           2.49G        10G           113      10000
/scratch        1.25G         1T            40      250000
Type 'showquota' to view these quotas again. 

Note: It is important to pay attention to this information, as it shows how much space has been used in each directory. Hitting a quota limit can cause problems for the user and should be avoided.
More information on the specific file systems including limitations and information about expansions can be found on the File Systems page.

Modules

The Modules system organizes the multitude of packages we have installed on our clusters so that they can be easily maintained and used. Any software you would like to use on Terra should use the Modules system.
NO modules are loaded by default.

The main command necessary for using software on Terra is the load command. To load a module, use the following command:

[NetID@cluster ~]$ module load [packageName]

The specification of packageName in the load command is case sensitive and it should include a specific version. To find the full name of the module you want to load, use the following command:

[NetID@cluster ~]$ module spider [packageName]

More information on the Modules system can be found on the Modules System page.