Google servers go down if half internet users ddos it?

[Mr Happy]

Google has over 20 thousand servers. Not just one massive one that everyone connects to. So its pretty much impossible.

Are you crazy. It's way way more than that. It's at least half a million.

Google runs on hundreds of thousands of servers—by one estimate, in excess of 450,000—racked up in thousands of clusters in dozens of data centers around the world.

and that figure is from 2006. Think about how much it's grown since 2006.

I'd say, like zakuza linked to the wiki answers, it's more like a million.