This topic describes the protection modes provided by OceanBase Database.
OceanBase Database provides the following three protection modes:
Maximum performance
This is the default protection mode. It protects user data and maximizes the performance of the primary cluster. In this protection mode, a transaction can be committed immediately after the persistence of REDO logs in the primary cluster is completed. REDO logs are asynchronously transferred to standby clusters, without affecting the transaction commits in the primary cluster. Therefore, the performance of the primary cluster is not affected by the synchronization latency of standby clusters.
Maximum protection
This protection mode maximizes data protection to prevent data loss when the primary cluster fails. In this protection mode, a transaction can be committed only after the persistence of REDO logs in the primary cluster and the standby cluster that is in SYNC mode is completed.
In this protection mode, you can configure only one standby cluster in SYNC mode, and other standby clusters must be in ASYNC mode. If the standby cluster in SYNC mode is unavailable, the primary cluster stops the write service.
Maximum availability
This protection mode maximizes data protection without compromising cluster availability. By default, a transaction can be committed only after the persistence of REDO logs in the primary cluster and the standby cluster that is in SYNC mode is completed. However, when a failure of the standby cluster in SYNC mode is detected, the primary cluster no longer waits for the synchronization to complete. Instead, the services of the primary cluster are recovered in the same way as that in maximum performance mode to ensure availability of the cluster. After the services of the standby cluster in SYNC mode are recovered, the primary cluster automatically resumes the SYNC mode to provide maximum data protection.
In this protection mode, you can configure only one standby cluster in SYNC mode, and other standby clusters must be in ASYNC mode.
For use constraints on the protection mode, see Precautions and use constraints.