Theta OS Upgrade Nearing Completion

The ALCF’s major update of Theta’s OS versions is nearing completion. 

We are upgrading ALCF-Theta from its current SLES12/CNL6 configuration to SLES15/CNL7. This will require some user codes to be rebuilt and/or relinked.

We are also upgrading Theta’s Sonexion Lustre filesystem.

These necessary enhancements will allow us to make newer software versions available, improve security and reliability, and help pave the way for Theta to connect with the coming global filesystem. For more information, including a full list of known improvements and impacts associated with the upgrade, please read the upgrade notes:

In addition, please be aware that the upgrade will change adaptive routing from “Adaptive 0” to “Adaptive 3". This change will result in positive overall performance improvement for applications especially those that are sensitive to network latency (for more information, see: If you have questions or feedback on this change and its impact on application performance, please contact at us