HW requirements / High Traffic site



we would like to start using Piwik in our company, but before that, I would like to ask you about some informations about PIWIK HW requirements.

We have something about 200 sites and 500K pageloads daily (for all sites).

Could you please provide information about recommended HW setup (how much RAM on the server is needed, how much disk space…) ?

Thanks a lot