Hi everyone!

I am about to run a survey (15 pages, only basic input questions, no interaction between participants or live-pages) with oTree with a potential participant number of up to 500,000. However, when I try to set up a session with 500,000 participants, creating this session takes ~10 hours. Once the session is set up and I want to look into it through the 'data'-tab, the server overloads and I receive a runtime error. Additionally, downloading data from the server also takes multiple hours and the server cannot be reached anymore, not from the admin nor the participant side. These problems are true for the localhost-server and also for using an actual server for running experiments.
Does anybody have an idea how to run such a very large session without facing serious server performance issues?

Thanks!

Wow, this orders of magnitude more than I ever tried. Have you timed starting up with say 50,000 participants? If that works then running ten independent servers might be a workaround.

This does not work, unfortunately. Participants are invited with one single link to everyone. So even if I would run the survey on 10 different servers, I would still need one redirecting link in a large session of 500,000 participants where they are just distributed to the other 10 servers. So this does not solve my problem. But thanks for the answer! I appreciate the idea.