That's not what I meant by a distributed file system. Is the metadata layer of ObjectiveFS distributed - scale-out. Can you add nodes to increase the metadata layer's capacity and throughput, so it can scale to handle millions of ops/sec? That's what I meant by a distributed file system (not just a client server, with a single metadata server).
There is no metadata server. The clients access S3 directly, and keep their own caches of both metadata and data. I don't know how the clients cootrdinate their writes and invalidate their caches, but somehow they do. From my perspective as a user, it just works.