Batch Limit Rules

Memory Limit:

It is strongly suggested to consider the memory use to the available per-core memory when users request OSC resources for their jobs. On Owens, it equates to 4GB/core or 124GB/node.

If your job requests less than a full node ( ppn< 28 ), it may be scheduled on a node with other running jobs. In this case, your job is entitled to a memory allocation proportional to the number of cores requested (4GB/core).  For example, without any memory request ( mem=XX ), a job that requests  nodes=1:ppn=1  will be assigned one core and should use no more than 4GB of RAM, a job that requests  nodes=1:ppn=3  will be assigned 3 cores and should use no more than 12GB of RAM, and a job that requests  nodes=1:ppn=28  will be assigned the whole node (28 cores) with 124GB of RAM.  

Please be careful if you include memory request (mem=XX ) in your job. A job that requests  nodes=1:ppn=1,mem=12GB  will be assigned one core and have access to 12GB of RAM, and charged for 3 cores worth of Resource Units (RU).  However, a job that requests  nodes=1:ppn=5,mem=12GB  will be assigned 5 cores but have access to only 12GB of RAM, and charged for 5 cores worth of Resource Units (RU).  See Charging for memory use for more details

A multi-node job ( nodes>1 ) will be assigned the entire nodes with 124 GB/node and charged for the entire nodes regardless of ppn request. For example, a job that requests  nodes=10:ppn=1 will be charged for 10 whole nodes (28 cores/node*10 nodes, which is 280 cores worth of RU).  

A job that requests huge-memory node ( nodes=1:ppn=48  ) will be allocated the entire huge-memory node with 1.5 TB of RAM and charged for the whole node (48 cores worth of RU).

To manage and monitor your memory usage, please refer to Out-of-Memory (OOM) or Excessive Memory Usage.

Walltime Limit

Here are the queues available on Owens:






 168 hours

1 node


longserial 336 hours 1 node
  • Restricted access (contact OSC Help if you need access)


96 hours

8 nodes

Jobs are scheduled to run within a single IB leaf switch


96 hours

81 nodes

Jobs are scheduled across multiple switches


168 hours

1 node

16 nodes in this class
Parallel hugemem 96 hours 16 nodes
  • Restricted access (contact OSC Help if you need access)
  • Use "-q parhugemem" to access it


1 hour

2 nodes

  • 6 nodes in this class
  • Use "-q debug" to request it 

Job Limit

An individual user can have up to 256 concurrently running jobs and/or up to 3080 processors/cores in use. All the users in a particular group/project can among them have up to 384 concurrently running jobs and/or up to 4620 processors/cores in use. Jobs submitted in excess of these limits are queued but blocked by the scheduler until other jobs exit and free up resources.

A user may have no more than 1000 jobs submitted to both the parallel and serial job queue separately.