Allocation

Resource Allocations on the Frontenac Cluster

This Wiki entry is meant to explain how resources are shared on the CAC Frontenac cluster. This includes default allocations in terms of Compute time as well as extended resources that were allocated by Compute Canada or that come from contributed systems. We also point out differences between the current Frontenac allocation scheme and the older scheme that was used on the now decommissioned SW/CAC clusters.

Default accounts

Our job scheduler on Frontenac is [SLURM https://slurm.schedmd.com/]. All resource allocations and limitations are applied through this scheduler. For a basic intro on how to use it, please see our scheduler help file.

Every user on our systems has at least one SLURM account, the default account. Users with access to extended resources have additional accounts corresponding to these allocations. These SLURM accounts have intrinsic restrictions and allow scheduling of jobs up to these limits.

The limitations of a default account are :

• Default allocation limit (one-year) cumulative : 50 core years
• Jobs are scheduled to the standard partition
• This partition excludes the high-memory and large-core-count nodes
• The default priority is 1 (low)
• No core limits
• Continued usage lowers the relative priority with respect to other jobs
• Default time limit : 3 hrs
• Maximum time limit : 14 days (2 weeks)
• Default memory limit : 1 GB
• Default number of cores : 1

RAC accounts

Users who have applied for and received a RAC allocation from Compute Canada, are accessing this allocation through a special RAC account.

The limitations of a RAC account are :

• RAC allocation limit : granted (<asked!) by Compute Canada (2017 RAC)
• Jobs are scheduled to the reserved partition
• No scheduling on the standard partition.
• This partition includes the high-memory and large-core-count nodes
• The RAC priority is 5 (enhanced)
• No core limits
• Continued usage lowers the relative priority with respect to other RAC jobs
• Maximum time limit : 28 days (4 weeks)
• Default time limit : 3 hrs
• Default memory limit : 1 GB
• Default number of cores : 1

Contributed accounts

Users who have applied for and received a RAC allocation from Compute Canada, are accessing this allocation through a special RAC account.

The limitations of a RAC account are :

• contributed allocation limit : 1 core year per core contributed
• Jobs are scheduled to the reserved partition
• No scheduling on the standard partition.
• This partition includes the high-memory and large-core-count nodes
• The contributed priority is 10 (high)
• Core limit : number of cores contributed
• Continued usage lowers the relative priority with respect to other contributed jobs
• Maximum time limit : 28 days (4 weeks)
• Default time limit : 3 hrs
• Default memory limit : 1 GB
• Default number of cores : 1

Comparison: Allocation on SW/CAC (SGE) vs Frontenac (SLURM)

Allocation Feature	SW/CAC (SGE)	Frontenac (SLURM)
Default allocation (compute)	48 core limit excludes dedicated systems job limits may apply	50 core years over 1 year standard partition low priority (1) no scheduling to "large nodes" job limits may apply
RAC allocation (compute)	fixed core limit according to allocation from Compute Canada associated with dedicated node scheduled to specific node by user	fixed core-years allocation over one year allocation from Compute Canada (less than ask!) scheduled to "reserved" partition at higher priority (5) no dedicated resources, reserved partition compete with other users of same priority
Contributed allocation (compute)	fixed core limit depending on size of contributed system allocation from depends on system size associated with dedicated node scheduled to specific node by user	fixed core-years allocation over one year allocation depends on system size scheduled to "reserved" partition at very high priority (10) no dedicated resources, reserved partition compete with other users of same priority
Limits	core limits: default 48 temporary extensions available RAC/contributed allocatgion run with extended limits global job limits may apply	no permanent core limits sanity core limits may apply to support fair-share usage lowers priority (fair share) RAC/contributed allocation increase priority no global job limits