Handle multiple NFS instances/disks

[julianhess]

Handle multiple NFS instances/disks

[agraubert]

Just to make sure we're on the same page, I think we had discussed two options, right?

wolF Task Spreading

Let wolF be entirely responsible for distributing jobs across the available NFS instances. Either rotate through, queuing one task/NFS or estimate the throughput needed by each task and use that to determine distribution of tasks

Canine Orchestrator Spreading

The Orchestrator can spread a single task across multiple NFS by chunking the input job spec and creating one localizer instance each

[julianhess]

Yup, those were the two options. The former option is by far the easiest, but it would preclude very large IO intensive scatter jobs.

[agraubert]

One of the things that has been bothering me is how we report/detect multiple nfs mounts so the orchestrator can shard a pipeline. What I think is the simplest solution is to allow the localization.staging_dir pipeline argument to also be an array. If it's an array, canine should distribute the job load across those NFS mounts (either by spreading jobs evenly or by fully loading one NFS before moving to the next).

Ie:

localization:
  staging_dir:
    - /mnt/nfs/a/
    - /mnt/nfs/b/
    - /mnt/nfs/c/

And then the orchestrator can create separate localizers for each NFS that it's using. Additionally, the --array argument to sbatch would allow us to modify the task ids so the pipeline still exists over a contiguous block of job ids