Attention

The ShARC HPC cluster was decommissioned on the 30th of November 2023 at 17:00. It is no longer possible for users to access that cluster.

Cryo-EM Facility nodes (School of Biosciences)

The School of Biosciences’ Cryo-Electron Microscopy Facility has purchased 3 nodes in ShARC.

that each have more than the standard number of cores for ShARC nodes (16).

Specifications

Three nodes (sharc-node135, sharc-node136, sharc-node138) each have:

Processors	2x Intel Xeon E5-2640 v4 processors (2.40 GHz, 10 cores per processor i.e. 20 total)
RAM	256 GB RAM (12.8 GB / CPU core)
NUMA nodes	2x
Networking	100 Gbps Omni-Path
Local storage	839 GB under `/scratch` (HDD)

Requesting Access

Access to the node is managed by Svet Tzokov (s.b.tzokov@sheffield.ac.uk; Electron Microscopy Facility Manager).

To use the nodes you must:

Be made a member of the cryoem Grid Engine (scheduler) Access Control List (ACL i.e. user group) by Svet Tzokov;
Submit jobs using the cryoem Grid Engine Project;
Start interactive jobs and batch jobs in cryoem.q Grid Engine Cluster Queue;

Running an interactive session

Once you have obtained permission to use the nodes you can request an interactive session on one of the nodes using:

qrshx -P cryoem -q cryoem.q

Here -P cryoem specifies that you want to use the cryoem project for your session, which gives you access to these big memory nodes and ensures that your interactive session can run in the cryoem.q job queue (as can be seen if you subsequently run qstat -u $USER from within your session).

The cryoem.q job queue has a maximum job runtime (h_rt) of 96 hours for interactive sessions (and batch jobs), which is much greater than is standard for interactive jobs on SHARC.

Submitting batch jobs

Jobs can be submitted to the nodes by adding the -P cryoem and -q cryoem.q parameters. For example, create a job script named my_job_script.sh with the contents:

#!/bin/bash
#$ -P cryoem
#$ -q cryoem.q

echo "Hello world"

You can of course add more options to the script such as a request for additional RAM (e.g. $# -l rmem=10G).

Run your script with the qsub command:

qsub my_job_script.sh

You can use the qstat command to check the status of your current job. An output file is created in your home directory that captures your script’s outputs.

See Batch Jobs for more information on job submission and the Sun Grid Engine scheduler.