Default:Limits

Default Execution Limits

Execution limits at the Centre for Advanced Computing are in place to provide greater flexibility in scheduling user applications. The following table shows the default limits that are currently in place. Note that our clusters are undergoing extensions and re-structuring, and that these limits are likely to change in the near future. Please check sporadically to keep up-to-date with them.

Global Job Limit: Users are limited to 48 executing jobs at any one time. This means that across the production clusters (M9000, SW and VictoriaFalls) each user can run up to 48 (total) production jobs simultaneously. Submitted jobs above that limit will remain in the queue until a job slot comes free.

To reflect the differences in processor slots, number of machines, CPU speed and memory available, the total maximum number of processes or threads that can be run at a given time are as follows

• M9000 Servers (m9k0001-8) 64 (default systems)
• SW Linux Cluster (sw0011-53) 48
• Victoria Falls (v01-73) 512

Important Note: Research groups will in many cases require more resources, especially in terms of thread/process numbers, and may fall outside of these limits. We will work with these users to ensure appropriate access. Any requests for enhanced access should include specifications for number of processors required, total amount of memory, and the expected maximum runtime(s). Contact the User Support group to ensure that this is arranged using the most appropriate resource.

Note that long-term extended usage requires a formal application to Compute Canada. Calls for such applications are currently issued once a year in the fall. We are announcing these calls on our web page. The allocation is done by a Research Allocation Committee (RAC).

Please note that scheduling of jobs using the commercial software packages Fluent and Abaqus involves a license check and must therefore remain subject to additional limits. These limits are presently suspended but will be re-instituted if the limit of available licenses is approached.

These limits makes the utilization of our resources more efficient, while allowing researchers to get their work done or to expand their research and address new problems.