Running 5.000 wordpress blogs

Hi all,

We’re about to complete at setup for running about 5.000 individual wordpress blogs.

My problem merely rely in the word of high availability. We want to put the blog across 2 to 3 webservers which are running at different locations around the world.

My question is, currently we have a command and control server which serves as the administration server. All changes to this server is synced through rsync to the webservers, but i kinda like to remove this single point of failure from our setup. My idea is to simply install W3 Total Cache and host all images on our CDN – all caching is done to a central memcache server. Is it then correct that no files are actually saved on the webservers because all media content will be on the CDN, pages and such will be in the database which is shared across all webservers?

I want to hear your ideas to make the blog running on multiple webservers to ensure high availability.