Seems really nice. Would love to see it how it compares to Ceph, we were considering Ceph for our container storage. For starters, it seems much more simpler to deploy.
Docker supports native RBD since version 1.8. Which should be both faster and more reliable than using the S3 gateway (though that has other benefits and becoming pretty good too).
I work at a company where object storage is something they have worked on for many years to get it stable. You can download it for free (it's Open Source)! Open vStorage is very easy to deploy through Ansible! Try it :)! https://www.openvstorage.com/https://github.com/openvstorage
