I've dealt with large scale systems design and administration in IT for over 6 years. For the last 8 month I've been working Booking.com, specializing in scaling our Graphite stack, improving its reliability and performance.

We at Booking.com have hundreds of backend servers, hundreds TB of data which we use to handles millions of metrics per second using our Graphite stack. The rate of growth is enormous and constantly growing.

I've spoken at public conferences in Russia, some of which are:
https://events.yandex.ru/lib/people/321/
https://expozilla.ru/past/event/2014_04-itlifeconf-spblinuxfest.html