While the LCRC batch queues are designed to handle the vast majority of work, we recognize that there are special circumstances that require exclusive use of a portion of our resources for a period of time, e.g., to meet an urgent deadline or to carry out certain kinds of benchmarks. Often we can meet such needs by reserving a specific number of nodes for your project for a specific period of time.
There are two kinds of reservations, (a) requests that are covered by the standard policy below, and (b) other special requests that require additional discussion and justification.
For a standard reservation that adheres to the policy below, send email to email@example.com with the name of the computer needed, number of nodes, desired start time, and duration (hours). We will email you with the scheduled start time. For all other cases send a note to firstname.lastname@example.org with a full description of your requirements and constraints, and tell us how to contact you by phone. We will call you to discuss it.
Standard Reservation Policy
- Reservations must be requested at least 8 business days in advance and are subject to availability of resources.
- Reservations cannot be requested more than once per quarter per project.
- Reservations are charged at the normal rate for the reserved time (regardless of whether or not you stop running jobs early or never run any jobs), plus the cost of the jobs to run on the nodes. So the total charge is 2x the normal rate if all the time is used.
- Reservations can spend a maximum of 20,000 core hours (i.e., 10,000 core hours towards the reservation time, and 10,000 core hours for jobs).
- Reservations create substantial perturbations to the scheduling of other jobs long before the reservation starts. Once a reservation is scheduled it cannot be rescheduled, and if you end up not needing or using it, the project will still be charged for the reservation time. It is like a non-refundable movie ticket.
Total Charged Time is considered to be the sum of Reservation Time and Job Time. Reservation Time is considered to be the amount of cores multiplied by the number of hours of the entire reservation. Job Time is the time used by jobs during the reservation.
User A wants to put in a reservation for 128 nodes for 4 hours on Fusion 9 days from now. Let’s say that during this reservation User A used 3,584 core hours.
Total Charged Time = Reservation Time + Job Time: the
Total Charged Time = 128 nodes x 8 procs x 4 hours + 3,584 yielding a Total Charged Time of 7,680 core hours.
User B wants to put in a reservation on Blues for 32 nodes for 8 hours 10 days from now. Let’s say that during this reservation User B used 4,092 core hours.
Total Charged Time = Reservation Time + Job Time: The
Total Charged Time = 32 nodes x 16 procs x 8 hours + 4,092 yielding a Total Charged Time of 8,188 core hours
User C wants to put in a reservation on Blues for 64 nodes for 16 hours 10 days from now. This request would need additional discussion and justification because the expected Total Charged Time will be greater than 20,000 core hours. The Total Charged Time could be over 30,000 core hours.