Delta CPU is the CPU-only portion of NCSA’s Delta system, an ACCESS-allocated high-performance computing resource designed for workloads that do not require GPU acceleration. Delta CPU is well suited for CPU-based computation, parallel computation, data analysis, software compilation, and pre/post-processing tasks.
Delta CPU nodes are dual-socket AMD EPYC 7763 “Milan” compute nodes with 128 CPU cores, 256 GB RAM, and 0.74 TB of local storage per node. CPU jobs run through the Slurm scheduler and can use Delta’s shared file systems, command-line batch environment, and Open OnDemand interfaces.
Jobs
Jobs on Delta CPU resources are submitted through the Slurm scheduler. Users can submit batch jobs with sbatch, start interactive jobs with srun or salloc, or access compute resources through Open OnDemand applications such as JupyterLab, VS Code Code Server, and noVNC Desktop.
Delta CPU jobs should use the CPU partitions: cpu for standard production jobs, cpu-interactive for short interactive sessions, and cpu-preempt for checkpointing-capable jobs that can tolerate interruption. The standard cpu and cpu-preempt partitions allow jobs up to 48 hours, while the cpu-interactive partition has a 1-hour maximum duration.
Node sharing is the default behavior for Delta jobs. Users who need exclusive access to a CPU node can request all consumable resources for the node or use Slurm options such as --exclusive --mem=0. CPU and GPU allocations use separate local charge accounts, so CPU jobs should be submitted using the appropriate Delta CPU account.
For more information about running jobs on Delta, see the NCSA Delta [Running Jobs] documentation.
Queue specifications
Metrics updated 2026-06-16
| Name | Purpose | CPUs | GPUs | RAM | Jobs
30 days
|
Wait Time
30-day trend
|
Wall Time
30-day trend
|
|---|---|---|---|---|---|---|---|
| cpu | Standard CPU queue for production batch jobs | 128 | 256GB | 451,657 |
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| cpu-interactive | Interactive CPU sessions for development, testing, debugging, compiling, and short interactive work | 128 | 256GB | 1,939 |
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| cpu-preempt | Preemptible CPU jobs for checkpointing-capable, flexible, lower-priority workloads | 128 | 256GB | 88 |
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Datasets
| Name | Description |
|---|---|
| ColabFold | ColabFold predicts protein folding structures and complexes using MMseqs2, which gives faster performance than AlphaFold. The ColabFold databases are available on Delta at |
| ImageNet | ImageNet is an image database organized according to the WordNet hierarchy, where each node of the hierarchy is depicted by hundreds to thousands of images. ImageNet database(s), version ILSVRC 2012–2017, are available on Delta at |
| alphafold | Protein structure prediction datasets used for bioinformatics research with AlphaFold. |
| models(ollama) | Pretrained large language models used with Ollama for local inference and AI experimentation. |
Storage
File System
| Directory | Path | Quota | Purge | Backup | Notes |
|---|---|---|---|---|---|
| HOME | /u | 100 GB; 750,000 files | Not purged | 30 days | Area for software, scripts, job files, and so on. Not intended as a source/destination for I/O during jobs. |
| PROJECTS | /projects | 500 GB. Up to 1-25 TB by allocation request. | Not purged | No | Area for shared data for a project, common data sets, software, results, and so on. |
| WORK-HDD | /work/hdd | 1000 GB. Up to 1-100 TB by allocation request. | Not purged | No | Area for computation, largest allocations, where I/O from jobs should occur. (this is now your scratch volume) |
| WORK-NVME | /work/nvme | NVME space is available upon request. | Not purged | No | Area for computation, NVME is best for lots of small I/O from jobs. |
| TMP | /tmp | 0.74 TB (CPU) or 1.5 TB (GPU). Shared or dedicated depending on node usage by jobs. | Purged after each job | No | Locally attached disk for fast small file I/O |
File Transfer
Delta supports several methods for moving data to and from the system. Users may use scp or rsync for small to modest transfers, while Globus is recommended for large data transfers. GUI applications that use SSH, SCP, or SFTP must support Duo multi-factor authentication.
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.
The Delta Globus endpoint provides access to Delta home directories and shared project/work file systems, including /work/hdd and /work/nvme.
For more information, see the NCSA Delta [File Sharing] and [Transferring Data] documentation.
| Supported Methods | Data Transfer Node | URL |
|---|---|---|
| GLOBUS | RECOMMENDED | https://app.globus.org/ | |
| SCP | dt-login[01-04].delta.ncsa.illinois.edu | |
| RSYNC | dt-login[01-04].delta.ncsa.illinois.edu |
Login to Delta CPU
Direct access to the Delta login nodes is available via SSH. To log in, users must have their NCSA username, password, and complete NCSA Duo multi-factor authentication. Delta provides a total of four login nodes, labeled 01 through 04.
When setting up access, users should be prepared to address components such as their NCSA account, the Duo app for authentication, SSH configuration, and SSH key pairs. It is important to note that the use of SSH key pairs is disabled for general use. Even principal investigators are not permitted to use SSH key pairs in place of two-factor authentication. The only exception applies to principal investigators with a Gateway allocation. This does not apply to most projects, but if Gateway account key pair access is required, a support ticket must be submitted.
In addition to SSH access, Delta also provides access through other portals such as Open OnDemand, which can be used for a more user-friendly interface and additional functionality. For maintaining persistent login sessions, the tmux multiplexer is available on all Delta login nodes. This utility allows users to run multiple programs within a single terminal, detach sessions while keeping processes running, and later reattach them from a different terminal.
For more information about accessing Delta, see the NCSA Delta [Delta Login Methods] documentation.
SSH Login
$ ssh <your_username>@login.delta.ncsa.illinois.edu