Jobs and Queues

In a grid engine system, jobs correspond to bank customers. Jobs wait in a computer holding area instead of a lobby. Queues, which provide services for jobs, correspond to bank employees. As in the case of bank customers, the requirements of each job, such as available memory, execution speed, available software licenses, and similar needs, can be very different. Only certain queues might be able to provide the corresponding service.

To continue the analogy, the grid engine software arbitrates available resources and job requirements in the following way:

• A user who submits a job through the grid engine system declares a requirement profile for the job. In addition, the system retrieves the identity of the user. The system also retrieves the user's affiliation with projects or user groups. The time that the user submitted the job is also stored.

• The moment that a queue is available to run a new job, the grid engine system determines what are the suitable jobs for the queue. The system immediately dispatches the job that has either the highest priority or the longest waiting time.

• Queues allow concurrent execution of many jobs. The grid engine system tries to start new jobs in the least-loaded and most-suitable queue.