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Kestrel Job Partitions and Scheduling Policies#

Learn about job partitions and policies for scheduling jobs on Kestrel.

Partitions#

Kestrel nodes are associated with one or more partitions. Each partition is associated with one or more job characteristics, which include run time, per-node memory requirements, and per-node local scratch disk requirements.

Excluding the shared and debug partitions, jobs will be automatically routed to the appropriate partitions by Slurm based on node quantity, walltime, hardware features, and other aspects specified in the submission. Jobs will have access to the largest number of nodes, thus shortest wait, if the partition is not specified during job submission..

The Kestrel system configuration page lists the four categories that Kestrel nodes exhibit based on their hardware features. In summary, standard compute nodes on Kestrel have 104 cores and 256 GB of RAM. 256 of those nodes have a 1.7 TB NVMe local disk. There are also 10 bigmem nodes with 2 TB of RAM and 5.8 TB NVMe local disk.

The following table summarizes the partitions on Kestrel:

Partition Name Description Limits Placement Condition
debug Nodes dedicated to developing and
troubleshooting jobs. Debug nodes
with each of the non-standard
hardware configurations are available.
The node-type distribution is:
- 2 Bigmem nodes
- 2 nodes with 1.7 TB NVMe
- 4 standard nodes
- 8 total nodes
1 job with a
max of 2 nodes
per user.
01:00:00 max walltime.
-p debug
or
--partition=debug
short Nodes that prefer jobs with walltimes
<= 4 hours.
2016 nodes total.
No limit per user.
--time <= 4:00:00
--mem <= 250000
--tmp <= 1700000 (256 nodes)
standard Nodes that prefer jobs with walltimes
<= 2 days.
2106 nodes total.
1050 nodes per user.
--mem <= 250000
--tmp <= 1700000
long Nodes that prefer jobs with walltimes > 2 days.
Maximum walltime of any job is 10 days
525 nodes total.
262 nodes per user.
--time <= 10-00
--mem <= 250000
--tmp <= 1700000 (256 nodes)
bigmem Nodes that have 2 TB of RAM and 5.8 TB NVMe local disk. 8 nodes total.
4 nodes per user.
--mem > 250000
--time <= 2-00
--tmp > 1700000
bigmeml Bigmem nodes that prefer jobs with walltimes > 2 days.
Maximum walltime of any job is 10 days.
4 nodes total.
3 nodes per user.
--mem > 250000
--time > 2-00
--tmp > 1700000
shared Nodes that can be shared by multiple users and jobs. 32 nodes total.
No limit per user.
2 days max walltime.
-p shared
or
--partition=shared
sharedl Nodes that can be shared by multiple users and prefer jobs with walltimes > 2 days. 16 nodes total.
8 nodes per user.
-p sharedl
or
--partition=sharedl

Use the option listed above on the srun, sbatch, or salloc command or in your job script to specify what resources your job requires.

For more information on running jobs and Slurm job scheduling, please see the Slurm documentation section.

Shared Node Partition#

Unlike the other partitions, nodes in the shared partition can be shared by multiple users or jobs. This partition is intended for jobs that do not require a whole node.

Tip

Testing at NREL has been done to evaluate the performance of VASP using shared nodes. Please see the VASP page for specific recommendations.

Usage#

Currently, there are 32 standard compute nodes available in the shared partition. These nodes have 250GB of usable RAM and 104 cores. By default, your job will be allocated 1.024GB of RAM per core requested To change this amount, you can use the --mem or --mem-per-cpu flag in your job submission.

Sample batch script for a job in the shared partition
#!/bin/bash
#SBATCH --nodes=1 
#SBATCH --partition=shared         
#SBATCH --time=2:00:00    
#SBATCH --ntasks=26 # CPUs requested for job 
#SBATCH --mem-per-cpu=2000 # Request 2GB per core.
#SBATCH --account=<allocation handle>

cd /scratch/$USER 
srun ./my_progam # Use your application's commands here  

Accounting#

The equation for calculating the AU cost of a job is:

AU cost = (Walltime in hours * Number of Nodes * QoS Factor * Charge Factor)

In the shared node partition, the value for Number of Nodes can be a fraction of a node. This value will be calculated based on either the amount of cores or the amount of memory requested, whichever is a greater percentage of the total of that resource available on the node.

Example Job Cost Calculation

For example, if you request 125GB of RAM (half of the available RAM on the node), and 26 cores, you will be billed 5 AUs per node hour.

# To determine the Number of Nodes value: 
125/250 = 0.5

26/104 = 0.25 

Number of Nodes = 0.5

# Final calculation

1 hour walltime * 0.5 nodes * 1 QoS Factor * 10 Charge Factor = 5 AUs

Performance Recommendations#

Please see this page for our most up-to-date performance recommendations on Kestrel.