As it invites the world to play in a mysterious sandbox it likes to call "Caffeine," Google is testing more than just a "next-generation" search infrastructure. It’s testing at least a portion of a revamped software architecture that will likely underpin all of its online applications for years to come.
Speaking with The Reg, über-Googler Matt Cutts confirms that the company’s new Caffeine search infrastructure is built atop a complete overhaul of the company’s custom-built Google File System, a project two years in the making. At least informally, Google refers to this file system redux as GFS2.
Link – http://www.theregister.co.uk/2009/08/14/google_caffeine_truth/