Computational Cluster Programs

Computing on the Hoffman2 Cluster

 

Role of the Login Nodes

The Hoffman2 login nodes provide command line access to the Hoffman2 Cluster. For web-based access to the Hoffman2 Cluster, use the UCLA Grid Portal. The login nodes are meant for light-weight tasks such as submitting jobs and file operations (editing, copying). Any cpu-intensive or memory-intensive task, including compiling large programs, must be done either by batch job submission or in an interactive session on the compute nodes.

Any process on the login nodes which seriously degrades other users' use of the system may be terminated without prior notice by the System Administrator. Repeat offenders will have their accounts locked.

Reserve Adequate Memory and Processors

Because more than one job may run at the same time on the same multi-processor node, a job or interactive session which uses more memory or more processors than it has been allocated will adversely impact other jobs which are also running on that node. If you are not sure how much memory your program will use, you should reserve an entire node for your job.

You need to request at least as many processors as your program uses threads. Your job or interactive session doesn't get the exclusive use of more than one processor on a node unless you tell the Sun Grid Engine to use a parallel environment.

Jobs or interactive sessions using more processors or significantly more memory than was reserved with SGE may be terminated without prior notice by the System Administrator.

See Running a Batch Job on an ATS-Hosted Cluster or How to Get an Interactive Session through SGE for information about using SGE parallel environments to reserve additional memory or processors.

Running Interactive Programs

If you need to run your program interactively, you can request an interactive session from the Sun Grid Engine from the pool of compute nodes. Please see:

You do not need to do this for commercial programs like Matlab which already have suitable options built into their startup scripts. See Software Installed on ATS-Hosted Clusters for information about specific programs.

Running Batch Jobs

The Hoffman2 Cluster uses the Sun Grid Engine (SGE) for running jobs:

April 2010