DeltaAI is NCSA's Grace Hopper supercomputer, designed for AI/ML training. It comprises 152 nodes built on the NVIDIA GH200 superchip.
Jobs
Jobs on DeltaAI are submitted through the Slurm scheduler. Users can run batch jobs with sbatch,
launch interactive work with srun or salloc, or access compute resources through Open OnDemand
applications such as JupyterLab.
Node sharing is the default behavior. The smallest allocatable unit is a single GH200 superchip - roughly 1 GPU, 72 CPU cores, and 187 GB of RAM - so jobs do not need to request a whole node. Users who need exclusive access can request all consumable resources for the node or use Slurm options such as --exclusive --mem=0. All nodes are of a single type and any job can span any node.
DeltaAI charges jobs based on the resources reserved for the job, not the resources used. One
Service Unit (GPU Hour) is one GH200 superchip for one hour, and the number of superchips charged is the largest of: the GPUs requested, the CPU cores requested divided by 72, or the memory requested divided by 187 GB. A request for 1 GPU with 300 GB of memory is therefore charged 2 SU per hour, and a whole node is charged 4 SU per hour. Note that the RAM available to jobs via the Slurm --mem option is 10 to 15 percent less than the total installed, because of memory reserved for the operating system.
If you do not specify them, jobs default to a 30-minute wall-clock limit and 1000 MB of memory per
core. Jobs are not automatically requeued or restarted by default; add --requeue to enable it.
For more information about running jobs on DeltaAI, see the NCSA DeltaAI [Running Jobs]
documentation.
Queue specifications
Metrics updated 2026-06-16
| Name | Purpose | Nodes | CPU cores / node | GPUs / node | Node RAM | Jobs
30 days
|
Wait Time
30-day trend
|
Wall Time
30-day trend
|
|---|---|---|---|---|---|---|---|---|
| ghx4 | Default GPU queue with 4 GPUs per node for standard production jobs | 152 | NVIDIA Grace ARM (aarch64) (288 cores) | 4 NVIDIA H100 (96 GB vRAM) | 480 GB | 136,931 |
|
|
| ghx4-interactive | Interactive GPU sessions for developing, debugging, and testing; max 4 nodes per job, 8 node-hours per user, charged at 2x | 152 | NVIDIA Grace ARM (aarch64) (288 cores) | 4 NVIDIA H100 (96 GB vRAM) | 480 GB | 34,237 |
|
|
Storage
DeltaAI users have HOME, PROJECTS, and WORK file systems, plus per-node local /tmp. /work/hdd and /work/nvme are shared between Delta and DeltaAI.
DeltaAI does not provide a /scratch file system.
Snapshots are only available for data in your /u directory and are retained for 30 days. These snapshots are not backups - you are responsible for backing up your files in /projects and /work.
File System
| Directory | Path | Quota | Purge | Backup | Notes |
|---|---|---|---|---|---|
| HOME | /u | 100 GB, 750,000 files | Not purged | Yes (30 days) | Area for software, scripts, and job files. Not for I/O during jobs. Snapshots are retained 30 days and are not backups. |
| Projects | /projects | 500 GB, 300,000 files | Not purged | No | Area for shared data for a project, common data sets, software, results, and so on. Up to 1-25 TB by allocation request. |
| Work - HDD | /work/hdd | 1 TB, 500,000 files | Not purged | No | Area for computation, largest allocations, where I/O from jobs should occur. Best for large sequential I/O. Up to 1-100 TB by allocation request. Shared between Delta and DeltaAI. |
| WORK - NVMe | /work/nvme | 1 TB, 500,000 files | Not purged | No | Area for computation, NVME is best for lots of small I/O from jobs. Up to 1-100 TB by allocation request. Shared between Delta and DeltaAI. |
| /tmp | /tmp | 3900 GB | Purged after each job | No | Locally attached disk for fast small file I/O. Save results to other file systems before job ends. |
External Storage
For large data transfers, Globus is recommended. For smaller transfers, SCP or Rsync are recommended.
Helpful Commands: The quota command is useful for viewing your usage of file systems quota. The accounts command is useful for mapping ACCESS projects to local projects on DeltaAI accounts
File Transfer
Users may use scp or rsync for small to modest transfers, while Globus is recommended for large data transfers.
Files can also be shared externally from the /projects file system using Globus. To share data,
users should create a sharing directory under their project space, move or copy the data into
that directory, and connect to the "ACCESS Delta" Globus endpoint to create the shared
collection.
For more information, see the NCSA DeltaAI [File Sharing] and [Transferring Data] documentation.
| Supported Methods | Data Transfer Node | URL |
|---|---|---|
| GLOBUS | RECOMMENDED | Globus | |
| SCP | RECOMMENDED | dtai-login.delta.ncsa.illinois.edu | Transferring Files |
| RSYNC | RECOMMENDED | dtai-login.delta.ncsa.illinois.edu | Transferring Files |
Login to DeltaAI
2FA/MFA required for login
Login setup
To setup your login on NCSA, you will create your own NCSA account and use that. NCSA will reach out to you via email with your NCSA username. Follow the link listed in that email to set up your NCSA password and register for DUO 2FA.
Note that DeltaAI doesn’t support SSH keys for logging in. Therefore, when you setup your 2FA, be sure to save the backup codes that it lists for you. If you are not prompted for these, open https://identity.ncsa.illinois.edu/manage, select Manage DUO, and you will receive your login codes.