Just found Grav and very much like what I see. I am planning on building a members site, lots of copy/images for the benefit of customers of members and, back-end forums for member interaction with each other. This will be multilingual, global and could end up with millions of pages.
Search/query will be a feature and needs to be fast as the site grows.
Hi @geester! Millions of pages is quite huge. Grav can’t handle such an amount of pages at the moment. The upper limit is at around 5000 pages, and the comfortable zone is at <1000 pages. See the recent discussion on the Grav issue tracker.
Thus, in your case I suggest using a traditional database driven CMS to accomplish your needs.