The Ohio Supercomputer Center (OSC) is experiencing an email delivery problem with several types of messages from MyOSC. 

 OSC is preparing to update Slurm on its production systems to version 23.11.4 on March, 27. 

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 Oakley, it equates to 4GB/core and 48GB/node.

If your job requests less than a full node ( ppn< 12), 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=12  will be assigned the whole node (12 cores) with 48GB of RAM.  However, a job that requests  nodes=1:ppn=1,mem=12GB  will be assigned one core but have access to 12GB of RAM, and charged for 3 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 48GB/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 (12 cores/node*10 nodes, which is 120 cores worth of RU). A job that requests large-memory node ( nodes=XX:ppn=12:bigmem, XX can be 1-8) will be allocated the entire large-memory node with 192GB of RAM and charged for the whole node (12 cores worth of RU). A job that requests huge-memory node ( nodes=1:ppn=32 ) will be allocated the entire huge-memory node with 1TB of RAM and charged for the whole node (32 cores worth of RU).

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

GPU Limit:

On Oakley, GPU jobs may request any number of cores and either 1 or 2 GPUs ( nodes=XX:ppn=XX: gpus=1 or gpus=2 ). The memory limit depends on the ppn request and follows the rules in Memory Limit.

Walltime Limit

Here are the queues available on Oakley:

NAME

MAX WALLTIME

MAX JOB SIZE

NOTES

Serial

168 hours

1 node

 

Longserial

336 hours

1 node

Restricted access

Parallel

96 hours

125 nodes

 

Longparallel

250 hours

230 nodes

Restricted access

Hugemem

48 hours

1 node

32 core with 1 TB RAM

nodes=1:ppn=32

Debug

1 hour

12 nodes

 

Job Limit

An individual user can have up to 256 concurrently running jobs and/or up to 2040 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 2040 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. Jobs submitted in excess of this limit will be rejected.