This topic describes the basic concepts and physical architecture of an OceanBase cluster.
OceanBase Database is a distributed database that consists of multiple physically scattered database units. These database units are logically unified by the computer network to form an OceanBase cluster.
An OceanBase cluster consists of multiple zones. A zone is a logical container for node management. Generally, a group of nodes in the same zone have similar disaster recovery attributes. A zone is usually an independent physical deployment unit, which can be an Internet Data Center (IDC), an availability zone in a cloud, or an independent rack. You can deploy your OceanBase cluster across different zones to implement fault isolation and quick recovery when a zone fails.
OceanBase Database is a single-process software solution. Its process is named observer. Generally, one physical server or virtual machine (VM) runs one observer process that is uniquely identified by an IP address and a port number. This server is called an OBServer node or simply a node. The observer process is the core component of OceanBase Database and provides all database kernel features, such as the SQL engine, storage engine, and transaction engine. The process also provides distributed features such as RPC communication, partition management, and load balancing.
The typical deployment architecture for an OceanBase cluster to provide high data security and service availability is three IDCs in the same region. In this deployment architecture, an OceanBase cluster is distributed in three IDCs in the same city. Three replicas of the same data are distributed across three IDCs. The following figure shows the deployment architecture.
In the preceding figure, the OceanBase cluster is deployed in three IDCs (corresponding to three zones) in the same city (corresponding to one region). Three servers (corresponding to three nodes) are deployed in each IDC.
OceanBase Database supports cross-region deployment with the regions located far away from each other for the purpose of geo disaster recovery. A region can contain one or more zones. For example, in the three IDCs across two regions and five IDCs across three regions deployment modes, one region can contain more than one zone.