Authentication through identity federation is becoming widespread in educational settings. One of the foreseeable effects was increasingly resource-heavy systems, stretching requirements in terms of performance and availability of SP and IdP blocks to unprecedented levels. And that's where we are now. The GAR project from the French national education department aims to give six million secondary school students simultaneous access to educational resources. It remains to be seen whether Shibboleth can deal with this. To answer this question, RENATER and the Rennes education authority carried out load testing of an authentication infrastructure based on Shibboleth. The tests were carried out on isolated servers, but also on load balancing infrastructures. The poster presents the experimental approach taken, the thresholds encountered and the optimised settings that allowed the required load to be reached.