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Cluster · Gefion HPC

P1 Gefion HPC

The P1 Gefion HPC is a sandbox with on-demand H100 GPUs on Gefion. Use it to develop, test and pilot a workload on the hardware generation it will scale up on. Full 8-GPU production nodes need separate funding, such as a Novo Nordisk Foundation (NNF) compute voucher or another allocation. A workload that already runs here is what you apply with.

Getting Access

Who's eligible?

Requirements: PhD or higher (exceptions may apply), valid Danish university email, and registered P1 affiliation.

Do I need to talk to someone first?

No. The optional workload survey tells the P1 compute coordinator about your workload, and helps us plan production nodes if your project scales.

How do I sign up?

  1. Request P1 affiliation in your P1 profile (Update Profile in the header). P1 staff approve it.
  2. Fill in the sandbox sign-up form below. A DCAI team member then contacts you with a DCAI username and initial-setup-password.
P1 Gefion Sandbox Sign-up Form · Requires an approved P1 affiliation.
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P1 Gefion Sandbox Sign-up Form

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What if I don't qualify?

PhD P1 affiliates and above can skip this section. If you are a P1 member currently enrolled in an MSc, a research assistant (RA) role, or similar, you are not eligible for access without a written approval of exception from a responsible person (a P1 co-lead or faculty member) who can vouch for your request. Fill in the form and have the responsible person send a confirmation to compute-governance-p1@aicentre.dk so they can audit the request. The exception applies across all P1 clusters.

P1 HPC Access Exception Form · Requires sign-off from a P1 co-lead or faculty member.
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P1 HPC Access Exception Form

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Connecting

bash
aicentre check -p gefion --connect

aicentre check shows what your machine needs for Gefion: the Host block for ~/.ssh/config and when to sign in to DCAI again. Then it tests the login. DCAI's documentation has the details.

Using the Cluster

The sandbox runs Slurm. Submit GPU work as batch jobs instead of holding an interactive session open.

  • Every job names the Slurm account it is charged to. P1's default account is iu_0096 (--account=iu_0096). A project with its own account uses that one instead.
  • Nodes have 2 TB of memory, so size --mem for the data a job loads, not its GPUs.
  • The P1 partition is on Gefion's open system. The login node reaches public git hosts and package indexes.
  • Large transfers use the SFTP endpoint xfer.dcai.dk. To get your public IP whitelisted, send DCAI support the output of curl ifconfig.io.

From the gallery:

See every example that runs on P1 Gefion HPC.

Policy & Support

What are the limits?

Compute

Max wall time
Not published; ask the compute coordinator before planning a long run
GPUs per job
2
GPUs at once, per person
4, as 2 concurrent jobs of 2 GPUs, more while GPUs sit idle

Storage

Home directory
25 GB
Project storage
500 GB default
Shared pool
300 TB
  • 16 H100 GPUs in total, shared by all sandbox users
  • User accounts are individual and non-transferable
  • An account can belong to one or more Gefion projects

Limits may change to meet the needs of P1 students and faculty.

How much storage do I get?

Home directories hold 25 GB, so keep datasets and checkpoints in your project space (500 GB default). Data sent to the SFTP endpoint lands in a staging area first and counts twice until you delete the staged copy.

Use cluster storage as working space, not an archive. Keep code in git and a second copy of anything you cannot regenerate on institutional storage or your own machine. Before a project ends, ask the compute coordinator what to move off.

What if I need more GPUs?

The default limit is 2 concurrent jobs of at most 2 GPUs each. When GPUs are idle on P1's two NVIDIA DGX H100 nodes (account iu_0096), you can go past it. Check what is free with sinfo and submit the larger job. No request is needed.

Default per-user limits keep the cluster fair when demand is high. Use this form when a run needs more than the default and needs to be protected: a multi-day training, a deadline, or a workload that cannot checkpoint. Tell us the size and the window, and the compute coordinator arranges it with the cluster operator.

Planned GPU Allocation · Tell us which cluster, how many GPUs, for how long, and by when.
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Planned GPU Allocation

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Who do I contact?

Technical Support
Broken or missing packages, scheduler issues
DCAI Support Team
Policy Support
Priority access, queueing, access exceptions
compute-governance-p1@aicentre.dk
General Questions
Open chat with the P1 compute community
#compute #ask-compute
Compute Coordinator
Onboarding, workload guidance, general questions. Always happy to help
Helped with your work? Acknowledge ORCID 0000-0002-2740-1651
workload survey bstja@dtu.dk

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Hardware Specification

Nodes
2× NVIDIA DGX H100 (8 GPUs each)
GPUs
16× H100 SXM, 640 GB GPU memory, around 32 petaFLOPS FP8
CPU per node
2× Intel Xeon Platinum 8480C (56 cores each)
RAM per node
2 TB
Interconnect
NVLink at 900 GB/s GPU to GPU, InfiniBand up to 400 Gbps
Shared storage
300 TB, 500 GB default quota
Home directory
25 GB
Operating system
NVIDIA DGX OS (Ubuntu based)
Scheduler
Slurm