node. A host machine that runs one or more OpenStack Object Storage services. Proxy node. Runs Proxy services. Storage node. Runs Account, Container, and Object services. Ring. A set of mappings between OpenStack Object Storage data to physical devices. Replica. A copy of an object. By default, three copies are maintained in the cluster. Zone. A logically separate section of the cluster, related to independent failure characteristics. To increase reliability and performance, you can add additional proxy servers. This document describes each storage node as a separate zone in the ring. At a minimum, five zones are recommended. A zone is a group of nodes that is as isolated as possible from other nodes (separate servers, network, power, even geography). The ring guarantees that every replica is stored in a separate zone. This diagram shows one possible configuration for a minimal installation: