Service Breaks

We strive to perform all maintenance with minimal impact to our users. However, on occasion we need to completely take a system down or to significantly degrade its performance.

Puhti and Mahti

Planned breaks on full system

Planned service breaks are announced at least three weeks in advance . It allows sufficient time for all running jobs to complete safely.

Puhti and Mahti supercomputers normally have maintenance breaks scheduled on the first Tuesday of every month. We always announce the planned duration of the break in advance and send updates in case of changes.

The jobs you run will not be interrupted by maintenance breaks. Maintenance windows are always reserved in advance, and only jobs that can safely finish before them are allowed to run. Thus, very short jobs can run even only moments before a maintenance break.

Planned breaks on puhti web interface

Planned service breaks are announced at least one week in advance .

Puhti web interfaces has maintenance breaks scheduled bi-weekly on Tuesdays. We announce the service break in the web interface notification, as well as on this page. The duration is typically one hour, between 9 - 10.

Unplanned breaks

Occasionally we may need to perform urgent maintenance due to technical or security reasons. In these cases we announce the break and reserve the time window for it as soon as possible.


Information about LUMI service breaks can be found here:

Other services

  • Sensitive Data services (SD Desktop and SD Connect) are maintained on the first Wednesday of every month. We always inform users by email about any additional service breaks.
  • Fairdata services' planned maintenance breaks are listed on

Service Breaks