The database system plays a crucial role in storing and querying data in various applications. It is especially important for the data security and business continuity of enterprises. To achieve these goals, high availability is a key consideration in the design of the database system. This involves ensuring both the high availability of services and the reliability of data. In this topic, we will focus on the technologies used in OceanBase Database to ensure business availability. For more information about technologies related to data reliability, see Backup and restore.
OceanBase Database offers various technologies to ensure high availability of services, such as intra-cluster multi-replica disaster recovery and inter-cluster primary/standby disaster recovery.
The multi-replica disaster recovery technology is designed for single-cluster scenarios where transaction logs are persisted and synchronized among multiple replicas. The Paxos protocol ensures log persistence for the majority of replicas, enabling disaster recovery through member changes.
The primary/standby disaster recovery technology is designed for multiple-cluster scenarios where transaction logs are transmitted across clusters to provide log-based physical hot backup services. In version 4.x, OceanBase Database uses an independent primary/standby architecture, allowing you to create primary and standby tenants. Logs are transmitted through a third-party log service, and clusters are no longer centralized, providing greater flexibility in cluster management.
Note
OceanBase Database v4.0.0 does not support primary/standby disaster recovery.
Both technologies serve different purposes. Multi-replica disaster recovery is for quick fault recovery and zero data loss in cases of failures of a minority of OBServer nodes in a single cluster. Primary/Standby disaster recovery, on the other hand, is suited for cross-region geo-disaster recovery and high availability scenarios, such as failures of a majority of OBServer nodes or software bugs. However, this technology is not applicable to the deployment mode of five IDCs across three regions. The two technologies complement each other and ensure business continuity, with logs transferred asynchronously from the primary tenants to standby tenants. Note that only the maximum performance protection mode is available. Therefore, for strong data consistency during disaster recovery, use multi-replica disaster recovery technology.