capacity-computing.md

!!!warning This page has not been updated yet. The page does not reflect the transition from PBS to Slurm.

Capacity Computing

Introduction

In many cases, it is useful to submit a huge (>100) number of computational jobs into the PBS queue system. A huge number of (small) jobs is one of the most effective ways to execute embarrassingly parallel calculations, achieving the best runtime, throughput, and computer utilization.

However, executing a huge number of jobs via the PBS queue may strain the system. This strain may result in slow response to commands, inefficient scheduling, and overall degradation of performance and user experience for all users. For this reason, the number of jobs is limited to 100 jobs per user, 4,000 jobs and subjobs per user, 1,500 subjobs per job array.

!!! note Follow one of the procedures below, in case you wish to schedule more than 100 jobs at a time.

• Use Job arrays when running a huge number of multithread (bound to one node only) or multinode (multithread across several nodes) jobs.
• Use HyperQueue when running a huge number of multithread jobs. HyperQueue can help overcome the limits of job arrays.

Policy

1. A user is allowed to submit at most 100 jobs. Each job may be a job array.
2. The array size is at most 1,000 subjobs.