Installation of the Roihu supercomputer begins

Roihu is Finland’s next national supercomputer, designed and built specifically to meet the needs of Finnish researchers. It will replace the current supercomputers Mahti and Puhti and elevate Finland’s national computing capacity to a new level, tripling it compared to the current systems.

Roihu will serve a wide range of scientific disciplines, from artificial intelligence to traditional simulations. The capability to analyze sensitive data is also being developed. The ability to process sensitive information, such as health records or ecological datasets, opens entirely new possibilities for research. At the same time, access to such data must be strictly controlled, and information security must not be compromised at any stage.

Roihu will also be used in higher education, which ensures the competence of future generations of researchers in all fields of science and industry.

Available to researchers in March 2026

According to the current schedule, the installation phase will continue until early December, after which Roihu will be handed over to CSC for acceptance testing. If all goes well, the pilot phase for researchers will begin in February 2026, and Roihu will be opened for general use in March 2026.

Puhti’s computing services will be shut down one month after Roihu goes live. Puhti’s storage services and login nodes will remain available until the end of June, giving users time to transfer their data without rush. Mahti will be decommissioned in August 2026.

Mahti will have served CSC for approximately six years, and Puhti for 6.5 years.

“CSC is preparing the end-of-life plans for Mahti and Puhti in line with scientific needs and sustainability principles. In practice, we’ll donate the systems to suitable recipients for continued use or spare parts”, says Sebastian von Alfthan, Development Manager at CSC.

Roihu to be housed at the LUMI Data Center in Kajaani

“Roihu will be housed at the LUMI data center, which has undergone a year-long expansion project including planning, construction, and testing phases. The facility has been upgraded with additional power and cooling capacity to accommodate Roihu. The expansion project has progressed well, and the installation of Roihu’s hardware has even started slightly ahead of schedule,” said Juha Torvinen, Data Center Project Manager at CSC.

Hero image at the top: CSC

Sebastian von Alfthan
The author is responsible for CSC’s national supercomputing services and develops the high-performance computing ecosystem.