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Reducing the maximum runtime for Open OnDemand sessions to 24 hours

On Monday 3rd November 2025, we will be implementing a change to reduce the maximum runtime for all Open OnDemand applications from 240 hours (10 days) to 24 hours.

Over the past 12 months, we have observed a growing number of Open OnDemand sessions remaining idle for several days. These long-running, inactive sessions occupy valuable cluster resources, contributing to longer queueing times for all users. As the number of Open OnDemand users continues to grow, this change is necessary to ensure fair and efficient use of cluster resources.

Open OnDemand applications are designed for short term interactive tasks lasting less than one day (as referenced by one of the Open OnDemand developers in this discourse post). Command-line batch jobs should be considered for computational tasks.

By introducing this new limit, we aim to achieve the following improvements for everyone:

  • Reduced number of queued Open OnDemand jobs
  • Shorter queueing times for all users
  • More efficient utilisation of cluster resources

If this change will have a significant impact on your research, please contact us to discuss your requirements.