I am planning to use Azure Batch Service. I will add several permanent jobs (in a permanent pool), and add new tasks to job now and then. Therefore number of completed (and incomplete) tasks will be increased over time. Should I delete the completed tasks? Does keeping these cause any problems?
It is recommended to delete completed tasks once you are sure that you no longer need them. Tasks take up disk resources on the compute node that ran them, and if you have lots of them that are never deleted (i.e., cleaned up), you run the risk of exhausting disk space for future tasks.
You can also have the system automatically clean up the task directory for you after the task completes by utilizing task constraints -> retention time. Search this page for retentionTime.