Ceph Object Storage uses the Ceph Object Gateway daemon (radosgw), which is a FastCGI module for interacting with a Ceph Storage Cluster. Since it provides interfaces compatible with OpenStack Swift and Amazon S3, the Ceph Object Gateway has its own user management. Ceph Object Gateway can store data in the same Ceph Storage Cluster used to store data from Ceph Filesystem clients or Ceph Block Device clients. The S3 and Swift APIs share a common namespace, so you may write data with one API and retrieve it with the other.
Ceph Object Storage does NOT use the Ceph Metadata Server.