Changes of Default Memory Limits

Problem Description

Our current GPFS file system is a distributed process with significant interactions between the clients. As the compute nodes being GPFS flle system clients, a certain amount of memory of each node needs to be reserved for these interactions. As a result, the maximum physical memory of each node allowed to be used by users' jobs is reduced, in order to keep the healthy performance of the file system. In addition, using swap memory is not allowed.  

The table below summarizes the maximum physical memory allowed for each type of nodes on our systems:

Owens Cluster

NODE TYPE PHYSICAL MEMORY per node MAXIMUM MEMORY ALLOWED per node
Regular node 128GB 118GB
Huge memory node 1536GB (1.5TB)

1493GB

Pitzer Cluster

Node type physical memory per node Maximum memory allowed per Node 
Regular node 192GB 178GB
Dual GPU node 384GB 363GB
Quad GPU node 768 GB 744 GB
Large memory node 768 GB 744 GB
Huge memory node 3072GB (3TB) 2989GB

Solutions When You Need Regular Nodes

If you do not request memory explicitly in your job (no --mem

Your job can be submitted and scheduled as before, and resources will be allocated according to your requests for cores/nodes ( --nodes=XX --ntasks-per-node=YY ).  If you request a partial node, the memory allocated to your job is proportional to the number of cores requested; if you request the whole node, the memory allocated to your job is based on the information summarized in the above tables.

If you have a multi-node job (  nodes>1  ), your job will be assigned the entire nodes with maximum memory allowed per node and charged for the entire nodes regardless of --ntasks-per-node request.

If you do request memory explicitly in your job (with  --mem 

If you request memory explicitly in your script, please re-visit your script according to the following pages:

Pitzer: https://www.osc.edu/resources/technical_support/supercomputers/pitzer/batch_limit_rules 

Owens: https://www.osc.edu/resources/technical_support/supercomputers/owens/batch_limit_rules 

Supercomputer: 
Service: