Campus researchers have access to Strelka, Swarthmore's computer cluster.  To learn more about the capabilities of the system and obtain an account, email  

Technical Specifications

System Configuration

The cluster consists of 13 nodes with an additional head node to handle user logins and job scheduling. 

  • 8 mid-memory nodes (384GB RAM)
  • 3 high-memory nodes (768GB RAM)
  • 2 GPU nodes, each with 4x NVIDIA 2080 Ti GPUs
  • High speed Infiniband networking

Jobs are submitted through the Slurm job scheduling system.




CPUs18x Intel Xeon Gold 6230
Total Cores648
Total Memory4.6TB
User Storage100TB

Creating an Account

All users log in using an SSH public key.  For help, see information on how to Create an SSH Key.

To obtain an account, complete a Strelka Account Request

Once you have an account, you will be able to connect to Strelka.  

Logging in

If off campus, VPN is required to connect to Strelka 

Connecting with macOS and Linux

Start the Terminal program on your computer and enter the following command (replace "username" with your Swarthmore username).  Usernames are case sensitive, so use all lowercase letters.  


Once logged in, you will be in your home directory (/home/username) on Strelka.  You are connected to the head node which is where you can manage your files, compile programs, and submit jobs to the cluster. 

Connecting with Windows

Follow the instructions on the Connect to Strelka from Windows page.  

Transferring Files

There are several ways to copy files from your computer to Strelka.

macOS/Linux command line

Use scp command on your computer to copy files to Strelka:

scp <path to file on your computer> <your username>@strelka:/home/<your username>

Here is an example of user Alice Paul copying a files from a folder on her computer to her home directory on Strelka:

scp /Users/apaul1/votingdata/data.csv apaul1@strelka:/home/apaul1

It also works to copy files from Strelka to your computer:

scp <your username>@strelka:<path to file on Strelka> <path to folder on your computer>

Use the -r flag to copy multiple files or folders.  Here is an example of user Alice Paul copying all the .csv files from a folder on her computer to her home directory on Strelka:

scp -r /Users/apaul1/votingdata/*.csv apaul1@strelka:/home/apaul1

Windows Options

PuTTY SCP (PSCP) is a command line version of SCP for Windows.  

WinSCP is an open source file transfer application.  

CyberDuck graphical file transfer for macOS/Windows/Linux

CyberDuck is a free graphical program that can be used to transfer files to and from Strelka.  Download and install CyberDuck and then set up an SFTP connection to Strelka.

Submitting Jobs

To run code on Strelka, you need to submit a job to the queue.  The cluster runs the Slurm job management system (Slurm Quickstart).  Create a job submission script to specify the details of your job (e.g. how many nodes, how much memory required, how to run your job).  

There are three partitions or queues for different types of jobs

Partition NameDescriptionAvailable Nodes
computeGeneral purpose computationAll 8 nodes (40 cores each) are available in this queue
himemHigh memory requirements3 high memory nodes, each with 768GB RAM
gpuGPU nodes2 GPU nodes, each with four GPUs

Example Submission Script

Here is an example Slurm job submission script:

Sample Slurm submission script
#! /bin/bash
#SBATCH -t 1:00:00
#SBATCH -n 4
#SBATCH -p compute	
#SBATCH --output=/home/aruethe2/testcode/output/output_%j.log

cd $HOME/testcode
python  >> $HOME/testcode/output/testcode.out.$SLURM_JOB_ID

In the above example, the following parameters are set:

#SBATCH -t 1:00:00Maximum time to run1 hour
#SBATCH -n 4Number of CPU cores to request4 cores
#SBATCH -N 1Number of nodes to request1 node
#SBATCH -p computeWhich partition to usecompute partition
#SBATCH --output=/home/aruethe2/testcode/output_%j.logWhere to save the Slurm output for the job/home/aruethe2/testcode/output_%j.log
(%j will be replaced with a job number after the job is submitted)

After the parameters are set, the commands to run the code are added.  In this case, the job runs a Python script and sends the output to a file.  The variable $SLURM_JOB_ID is added to the output file path so the output filename is unique.Submission Process

To submit a job, type the following (replace "jobfilename" with the filename of the job submission script).

sbatch jobfilename

Other Useful Slurm Commands

See the Slurm Commands page.

Other Strelka Resources


If you publish a paper where the cluster was used for calculation, please include the following acknowledgement:

“This work used the Strelka Computing Cluster, which is supported by the Swarthmore College Office of the Provost.”


An Advisory Group has been set up to govern the decisions concerning Strelka.  The members of the Advisory Group are:

  • Tristan Smith, Physics
  • Vidya Ganapati, Engineering,
  • Glenn Stauffer, ITS 
  • Andrew Ruether, ITS

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