You're on the right track, but why the hell do you think your gmail lives on 'a server', much less in a fliesystem directly? GFS normally uses chunks 2^14 time

You're on the right track, but why the hell do you think your gmail lives on 'a server', much less in a fliesystem directly? GFS normally uses chunks 2^14 times larger than a traditional inode -- you'd use infrastructure built on top of it (like Bigtable) to store email and indexes of it. You could easily end up designing a system that stores the email bodies in Gmail in a content-addressed form just as an indexing method, and end up getting de-duplication for free.