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HPC @ Uni.lu

High Performance Computing in Luxembourg

Decommissioning of Gaia and Chaos

The situation

Our flagship Iris cluster has been in production since 2017 and as of this year features regular HPC nodes, large memory nodes and GPU-accelerated nodes. As announced in previous communications, it is now time to start the decommissioning process of our former production clusters Chaos and Gaia. They have been in operation since 2007 and respectively 2011, are not supported anymore by their vendors and cannot be maintained in a safe, working state.

The migration plan

To summarize and to ensure a smooth transition to the Iris cluster for all our users, the decommissioning will be organized in several steps:

  • Until August: job submission is still allowed, with user data fully accessible (read-write)
  • August-October: transition period with no new jobs allowed (clusters being drained of existing jobs) but data still available as read-write, for cleanup and archival
  • From October: data accessible in read only mode, for archival
  • By December: your migration to the Iris cluster must be fully completed, as in December Chaos and Gaia will be taken offline

What will happen to the data ?

This means that your HOME and WORK directories on the Chaos and Gaia clusters must be cleaned-up of any temporary, leftover files before October. You will then have until December to archive inactive data, and migrate any remaining active data to Iris. Your workflows, including software built in your user space and submission scripts must be ported to the Iris cluster (and the SLURM batch scheduler) before August — you can follow the OAR to SLURM guide and/or inspire from the launcher script proposed in the many Uni.lu HPC tutorials on Github.

If for any of these steps, you encounter problems, have concerns regards the planned procedure, or require specific advice, please do not hesitate to contact us using hpc-sysadmins[at]uni.lu.

With no answer (and thus an implicit acceptance of the above actions) and no action from your side, the data hosted on the Chaos and Gaia cluster will not be accessible anymore at the end of this year.

Outside of your personal HOME and WORK directories stored on Chaos and Gaia, we are planning the migration of the project directories from these systems. Note that in this case, we have sent individual mails to all project owners and members in order to organize the migration using another specialized workflow, better suited for the timely movement of huge amounts of data. Finally, be aware that any data remaining on the SCRATCH filesystem of Gaia will also be inaccessible as of December.

The University of Luxembourg HPC Team