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. Contains the SQLite databases.
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.
Region (optional): A logically separate section of the cluster, representing distinct physical locations such as cities or countries. Similar to zones but representing physical locations of portions of the cluster rather than logical segments.
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 are 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:
