Node locality
If you need to ensure your jobs are not running on a node shared by someone else, use this option. Note: if all nodes are being partially used by other users, then keep in mind your job will take longer to be scheduled. If you submit multiple jobs with this option, and they can fit (according to the resource requirements you requested) on one node, then the scheduler will prefer to run those jobs on the same node.
#PBS -W x=NACCESSPOLICY:SINGLEUSER