Overview of zone management

An OceanBase cluster consists of several zones. Zone is short for availability zone. A zone is a logical container that manages physical machines, usually a group of servers in the same IDC. At the physical level, a zone is usually equivalent to an equipment room, a data center, or an IDC. To deliver high-level data security and service availability capabilities, an OceanBase cluster is usually distributed in three IDCs in the same city, having three replicas of the same data distributed in the three IDCs, that is, three zones.

OceanBase supports cross-region deployment with the regions located far away from each other for remote disaster recovery. A region can contain one or more zones. For example, an OceanBase cluster is deployed in three IDCs in a city (region), with three servers in each IDC. In this case, the three servers in each IDC forms a zone. Notice

1. A region is not an object in OceanBase, but a key attribute of a zone.

2. Tenants, databases, and data partitions (tables and indexes) at different levels are configured with primary zones for high availability and load balancing.

3. For tenants, you can also configure a read-only zone (RZone) to deliver high availability and load balancing capabilities for read/write splitting. Compared with a primary zone, a read-only zone requires one or more replicas in addition to the original Paxos group.