[ceph-users] Namespace usability for mutitenancy

Hello. Had been someone starting using namespaces for real production for multi-tenancy? How good is it at isolating tenants from each other? Can they see each other presence, quotas, etc? Is is safe to give access via cephx to (possibly hostile to each other) users to the same pool with restrictions 'user per namespace'? How badly can one user affect others? Quotas restrict space overuse, but what about IO and omaps overuse?