📝 ARC Compute Server

ARC Compute Server (Oxford)

Login

To connect to the ARC server, use the SSH command with X11 forwarding to enable graphical output:

ssh -Y name@arc-login.arc.ox.ac.uk

X11 forwarding allows for graphical applications to be displayed on your local machine.

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Job Scheduling with SLURM

ARC uses the SLURM workload manager to handle job submissions. You can submit jobs, check their status, cancel them, or run interactive sessions.

Submit a Job

To submit a job, use the sbatch command:

sbatch example-job.sh

Check Queue Status

To check the status of your queued jobs:

squeue -u yourUsername

Customize Job

You can customize job submissions with the following options:

• Job Name: In your job script:

#SBATCH -J jobName

• Resource Requests:
• Number of tasks (CPUs):

--ntasks=<ntasks> # or -n <ntasks>

• Time limit:

--time <days-hours:minutes:seconds> # or -t <days-hours:minutes:seconds>

• Memory:

--mem=<megabytes>
# Example for 5 GB
--mem=5g

• Number of nodes:

--nodes=<nnodes> # or -N <nnodes>

Cancel Jobs

• Cancel all jobs under your username:

scancel -u yourUsername

• Cancel a specific job:

scancel JOBID

Run Single Commands

Use srun to run a command directly on the cluster:

srun -n 2 echo "This job will use 2 CPUs."

You can cancel the job with Ctrl+C.

Interactive Sessions

To start an interactive session, run:

srun --pty bash

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Module System

The module system allows you to load specific software environments.

List Available Modules

module avail

Load a Module

module load python # Example for loading Python

Use module avail to find the exact versions available.

Unload Modules

• Unload a specific module:

module unload python

• Unload all modules:

module purge

Check Loaded Modules

To see which modules are currently loaded:

module list

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File Transfer

You can transfer files between your local machine and the ARC server using scp or rsync.

Copy Files with SCP

Run this locally to copy a file to the ARC server:

scp local_file user@arc-login.arc.ox.ac.uk:remote_destination

To recursively copy a folder, use the -r flag:

scp -r local_folder user@arc-login.arc.ox.ac.uk:remote_destination

Sync Files with Rsync

Rsync is useful for monitoring transfer progress and resuming partial transfers:

rsync -avP local_file user@arc-login.arc.ox.ac.uk:remote_destination

Options:

• -a: Archive mode, preserves file attributes.
• -v: Verbose mode, shows transfer details.
• -P: Partial transfer support and shows progress.

Info

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