Logging in to Supercomputing Wales


Teaching: 20 min
Exercises: 15 min
  • Understand how to log in to the Supercomputing Wales hubs

  • Understand the difference between the login node and each cluster’s head node.

Logging in

Your username is your institutional ID prefixed by a. for Aberystwyth users, b. for Bangor users, c. for Cardiff users and s. for Swansea users. External collaborators will have a username beginning with x..

Aberystwyth and Swansea users (and their external collaborators) should log in to the Swansea Sunbird system by typing:

$ ssh username@sunbird.swansea.ac.uk

Bangor and Cardiff Users (and their external collaborators) should log in to the Cardiff Hawk system by typing:

$ ssh username@hawklogin.cf.ac.uk

If you use Windows and haven’t installed the Git bash shell, you can instead use PuTTY and enter either sunbird.swansea.ac.uk or hawklogin.cf.ac.uk in the hostname box.

What’s available?

Supercomputing Wales

These figures may still be subject to some change and might have been sourced from out of date documents.

Partition Number of Nodes Cores per node RAM Other
Swansea Compute 123 40 382GB  
Swansea GPU 4 40 382GB 2x Nvidia V100 (5120 core, 16GB RAM)
Swansea Data Lake 1 72 1500GB Installed with Swansea system, and intended for e.g. Hadoop and Elastic Stack users. Not integrated with the main Sunbird system; contact Support or your RSE team for access details.
Cluster Number of Nodes Cores per node RAM Other
Cardiff Compute 134 40 190GB  
Cardiff Compute AMD 64 64 256GB AMD EPYC CPUs, not fully operational
Cardiff HTC 63 40 190GB  
Cardiff High Memory 26 40 382GB  
Cardiff GPU 13 40 382GB 2x Nvidia P100 (3584 core, 16GB RAM)
Cardiff Dev 2 40 190GB  
Cardiff Data Lake 2 ? ? Will be installed later. Intended for Hadoop and Elastic Stack users.

Aberystwyth and Swansea users are expected to use the Swansea system and will need to make a case for why they would need to use the Cardiff system. Bangor and Cardiff users are expected to use Cardiff, and external users are expected to use the same system as the owner of the project of which they are a member.


Slurm is the management software used on Supercomputing Wales. It lets you submit (and monitor or cancel) jobs to the cluster and chooses where to run them.

Other clusters might run different job management software such as LSF, Sun Grid Engine or Condor, although they all operate along similar principles.

How busy is the cluster?

The sinfo command tells us the state of the cluster. It lets us know what nodes are available, how busy they are and what state they are in.

Clusters are sometimes divided up into partitions. This might separate some nodes which are different to the others (e.g. they have more memory, GPUs or different processors).

compute*        up 3-00:00:00      1   fail scs0042
compute*        up 3-00:00:00      1 drain* scs0004
compute*        up 3-00:00:00      2    mix scs[0018,0065]
compute*        up 3-00:00:00     86  alloc scs[0001-0003,0005-0017,0019-0035,0043-0046,0049-0064,0066-0072,0097-0122]
compute*        up 3-00:00:00     32   idle scs[0036-0041,0047-0048,0073-0096]
development     up      30:00      1   fail scs0042
development     up      30:00      1 drain* scs0004
development     up      30:00      2    mix scs[0018,0065]
development     up      30:00     86  alloc scs[0001-0003,0005-0017,0019-0035,0043-0046,0049-0064,0066-0072,0097-0122]
development     up      30:00     32   idle scs[0036-0041,0047-0048,0073-0096]
gpu             up 2-00:00:00      4   idle scs[2001-2004]


Logging into Supercomputing Wales

If you haven’t already:

  1. In your web browser go to My Supercomputing Wales and log in with your university username and password.
  2. Click on “Reset SCW Password” and choose a new password for logging into the HPC. Your username is displayed in the “Account summary” box on the main page. Its usually a./b./c./s. and your normal university login details.
  3. Log in to sunbird.swansea.ac.uk or hawklogin.cf.ac.uk using your SSH client.
  4. Run the sinfo command to see how busy things are.
  5. Try sinfo --long, what extra information does this give?

Key Points

  • ssh sunbird.swansea.ac.uk or ssh hawklogin.cf.ac.uk to log in to the system

  • sinfo shows partitions and how busy they are.

  • slurmtop shows another view of how busy the system is.