The main characteristics of Anansi are:

• CPU cores can be shared by up to 4 jobs

• GPU devices can be shared by up to 4 jobs

• Maximum number of GPU devices per job is 1 (100% GPU fraction)

• Maximum job walltime is 12 hours

In contrast to Hydra, where computational resources are allocated exclusively to single jobs, the resources of Anansi can be shared between multiple jobs. This applies to CPU cores which are shared transparently, and to GPUs which can be requested in fractions of a full device. Other resources like CPU memory are not shared.

We also limit the number of resources you can use across all your jobs running in Anansi. Any single user can use up to 16 CPU cores and up to 100% of a single GPU (4 GPU shards) across all their jobs on Anansi. Jobs submitted when this limit is already reached will wait in queue with a Slurm Job Reason code either being QOSMaxCpuPerUserLimit or (QOSMaxGRESPerUser). Those jobs will be held in queue until the other jobs of the user are finished and the resources are freed.

Single jobs requesting more than 16 CPU cores or more than 100% of a GPU (4 GPU shards) will be refused by the queue with the message:

Job violates accounting/QOS policy (job submit limit, user’s size and/or time limits)

This approach is specially useful for light-weight (interactive) tasks such as testing/debugging that can involve frequent idle periods. Hence, even though the size of Anansi is smaller than Hydra, users should be able to quickly find an available slot to run their short jobs.

Moreover, the maximum time a job can run in Anansi is limited to 12 hours, which further increases the availability of its resources.