Volume 5, Number 2
i-limit on Redwood
In conjunction with this week's upgrade to Redwood, an interactive job limit (i-limit) has been imposed on redwood. Henceforth, interactive jobs will be automatically deleted by the system once they accumulate over 30 minutes of CPU time across all processors. Previously, interactive jobs had not been as tightly constrained on redwood. However, with an increasing number of interactive jobs being run in recent months, interactive shell response time had begun to suffer, since all user sessions and interactive jobs compete with one another for only 8 CPUs that are reserved for such activities in a static CPUset.
The new redwood policy is consistent with the long-standing sweetgum 30-minute i-limit policy, and will work the same way. Users whose jobs are terminated for exceeding the limit will receive an automated email message to their account on that supercomputer, explaining what has happened.
Meanwhile, interactive jobs on mimosa remain strictly prohibited. Any interactive jobs detected on the cluster will be deleted immediately, and the user account restricted. By enforcing this no-interactive-job policy on mimosa, we ensure that each compute node assigned to a user job is exclusively available to that job.
To learn more about how to submit a PBS job on any MCSR system, please see MCSR's online PBS Tutorial.