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Breezy (University of Calgary research projects only)

***NOTE: On September 1, 2017, Breezy was withdrawn from general WestGrid service.  It is now available only to approved University of Calgary-based projects. This is part of a continuing process for handling the retirement of WestGrid systems. Please visit the Migration Process page for more information. Questions regarding Breezy should now be directed to, rather than

Breezy is one of a number of local computing resources available to University of Calgary researchers.  However, Breezy is an old cluster that should be viewed as a supplement to other, more modern, machines. For example, Compute Canada Cedar and Graham clusters will provide better performance, but, job waiting times may be shorter on Breezy. Please write to us at if you would like to discuss the details of the advantages and disadvantages of the various alternatives.

With 24 cores per node, sharing up to about 250 GB of available memory, Breezy is suitable for shared-memory parallel programs (such as those based on OpenMP). It can also be used for serial processing, particularly for programs requiring more than 2 GB of memory.

As of September 1, 2017, new Breezy accounts are being set up only for researchers associated with the University of Calgary. If you are a University of Calgary researcher and think that the software you would like to run is appropriate for the Breezy cluster, please write to with a subject line of the form "Breezy account request (your_username)" with a request for an account and a mention of the software you propose to use.

To log in to Breezy, connect to using an ssh (secure shell) client. For more information about connecting and setting up your environment, see the QuickStart Guide for New Users.

Batch jobs are handled by a combination of TORQUE and Moab software. For more information about submitting jobs, see the general Running Jobs page.

The maximum walltime limit for Breezy jobs is 7 days.

For a single user, the maximum number of jobs in the system at a time is 1000.

Since Breezy is often used for applications requiring large amounts of memory, one should specify a TORQUE mem parameter on the qsub command line (or in #PBS directives in the batch job script). Although the memory per node is nominally 256 GB, there is not quite that much available. Do not specify more than 250 GB for the mem or pmem resource requests or your job will get stuck in input queue waiting for memory that will never be available.

Another intended use for Breezy is for multi-threaded single-node applications. For such cases, use a resource request of the form -l nodes=1:ppn=24,mem=250gb, where ppn, the processors per node, is the number of cores required and the memory needed is specified with the mem parameter. Since Breezy compute nodes have 24 cores, that is maximum number you can specify for ppn. You can use smaller values for ppn and mem as appropriate for your calculation. However, if you are using less than 24 cores, it is important to limit the number of threads used by your application to the number of cores requested, so as not to interfere with other users' jobs, which may be assigned to the same node. Often this can be accomplished by setting the OMP_NUM_THREADS variable. See the example script in the OpenMP section of Running Jobs page for an example.

Please do not use the ncpus or procs parameters when requesting processors on Breezy. In the rare cases in which multiple nodes are used for a single job, use the -l nodes=n:ppn=24 format to request multiple nodes, where n is the number required.

The Breezy login node may be used for short interactive runs during development. Production runs should be submitted as batch jobs.

Storage Information on Breezy (University of Calgary research projects only)

Directory path Size Quota Command to check quota Purpose Backup Policy
/home 20 TB (Shared with Lattice and Parallel) 50GB Write to with a subject line of form "Disk quota for user your_user_name requested for Breezy"

Use your home directory for files that you want to save for longer than 30 days.


Users are responsible for their own backup.

/global/scratch 300 TB (Shared with Lattice and Parallel) 450GB Write to with a subject line of form "Disk quota for user your_user_name requested for Breezy"

Please note that /global/scratch is intended only for files associated with running jobs or waiting for post-processing.

Files older than 30 days are subject to deletion.

2015-05-30 - Updated purpose and backup policy for /home and /global/scratch file systems.
2015-07-29 - Added a note to clarify that large-memory serial jobs are acceptable for Breezy.
2015-11-09 - Replaced file system sizes and quota checking procedure.
2017-09-18 - Noted that Breezy is available only to U of C-based projects and updated maximum walltime limit to 7 days.