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  • 4 min read

Testing MattX with EESSI

Almost 2 decades ago openMosix was the hottest open source Single System Image (SSI) cluster out there. OpenMosix could migrate long running processes across a cluster and thus effectively allowing HPC workloads to be spread across a cluster or migrated to a node with more resources, with no changes to the code. The project however never got a 2.6 kernel port and thus was EOL by early 2008.

Earlier this year Matt Rechenburg, one of the original openMosix community members released MattX, the Modern SSI Cluster , which brought back the openMosix vibes. MattX lacked a test suite and thus I had a suite build. Initially the Mattx Test suite just spun up a number of VM's and migrated basic processes around to validate the new releases. Working on that Test suite I wondered if it weren't a good idea to take let some real HPC workloads migrate around, and where better to find them than in the EESSI demo project.

MattX Process Migration

  • 7 min read

EESSI activities at ISC'26

During the week of 22-26 June 2026, EESSI was part of the official program of the ISC'26 conference in Hamburg (Germany) in various ways.

Next to the Introduction to EESSI half-day tutorial and a Birds-of-a-Feather (BoF) session we organized ourselves, EESSI was also featured prominently in two other BoF sessions, including the one on the EuroHPC Federation Platform.

In addition, we gave presentations in two workshops, witnessed how EESSI got mentioned by speakers in other sessions, and had lots of interesting discussions with members of the HPC community at the ISC exhibit or when bumping into people in the hallway track.

  • 3 min read

lfoss/2025b now available in the EESSI RISC-V stack

The EESSI RISC-V software stack available through the dev.eessi.io/riscv repository now includes the lfoss/2025b toolchain.

This is an important milestone for the RISC-V enablement work in EESSI, since it brings a modern LLVM-based software toolchain to the growing collection of software available for RISC-V systems through EESSI.

  • 5 min read

MPI at Warp Speed: EESSI Meets Slingshot-11(bis)

Building on our initial HPE/Cray Slingshot‑11 results, we further refined MPI tuning and validated the setup using EESSI 2025.06.

The outcome is a significant performance improvement, bringing MPI support in EESSI much closer to vendor tuned Cray MPI environments.

  • 8 min read

Choosing EESSI as a base for MUSICA

MUSICA
(c) Matthias Heisler 2026

MUSICA (Multi-Site Computer Austria) is the latest addition to Austria's national supercomputing infrastructure. The system's compute resources are distributed across three locations in Austria: Vienna, Innsbruck, and Linz. We describe the process that led to the adoption of EESSI as a base for the software stack on the MUSICA system at the Austrian Scientific Computing (ASC) research center.

  • 7 min read

Using Spack on Top of EESSI: Best of Both Worlds

Spack + EESSI

The HPC software landscape offers powerful tools for managing scientific software, such as EasyBuild and Spack.

EESSI provides a ready-to-use software stack with thousands of optimized software installations that were built with EasyBuild.

Imagine you are working on an HPC system with EESSI already available. You have access to a wealth of optimized installations for scientific software packages, libraries, tools, as well as compilers. But you need to install a new tool or a specific version of a package that's not in EESSI yet.

You can already extend EESSI with new software through the EESSI-extend module. This utility provides you with a pre-configured EasyBuild installation that you can use to build packages from easyconfig files.

Like EasyBuild, Spack is a flexible build tool that also offers a vast repository of build recipes maintained by a large and active community, making it a familiar tool for many HPC users. By enabling Spack to leverage software installations already available in EESSI as dependencies, we can offer users the best of both worlds: the convenience of a pre-built, optimized software stack combined with the flexibility to quickly build new packages using tools they already know.

  • 4 min read

EESSI at FOSDEM'26

This year's FOSDEM exceeded all expectations a first-time attendee like me could have. Filled with interesting talks, wide range of diverse people and impactful projects, I bring back home a bag full of stickers, lovely memories and some Belgian chocolates.

Stickers