The problem is not to send those data. It's to fetch them on all your infrastructure. XAPI RRDs aren't meant to be accessed on that scale, it will clearly explode CPU usage on XOA, even with a moderate size infrastructure. Because those RRDs are sent in XML with a TON of data that you need to parse.
It would make more sense to have netdata (or telegraf) on earch host and send data to a central server.