Perform a failover

This topic describes how to perform a failover.

Scenarios

When the primary tenant becomes unavailable, you can perform a failover to switch a standby tenant to the primary role to provide services.

Prerequisites

• Make sure that you have the following permissions:

  • Resource Permissions : Cluster Maintenance or Tenant Maintenance permission
  • Menu Permissions : Permission on the Overview menu of Tenants

• In this topic, the standby tenant is specifically a standby tenant for which you want to perform a failover, and the primary tenant is specifically the primary tenant associated with the standby tenant. In a cascading primary/standby relationship between tenants, for example, Tenant A > Tenant B > Tenant C, both Tenant B and Tenant C are standby tenants. However, when you perform a failvover for Tenant C, Tenant C is called the standby tenant, and Tenant B is called the primary tenant.

  • The primary tenant is unavailable. If the primary tenant is available, you can decouple the standby tenant from the primary tenant.
  • The primary and standby tenants have been added to OceanBase Cloud Platform (OCP) for management. In multi-cluster mode, the primary and standby tenants can belong to different OCP clusters.
  • The standby tenant is available, and the cluster to which the standby tenant belongs is normal.

Procedure

1. Log on to the OCP console.

2. In the left-side navigation pane, click Tenants . On the Tenants tab, select the target standby tenant.

3. On the page that appears, click the More icon in the upper-right corner and select Failover from the menu.

4. OCP displays the consistency timestamps of all standby tenants of the primary tenant. We recommend that you perform a failover for the standby tenant with the latest consistency timestamp, because it contains the latest data.

   Click Failover to submit a failover task. After the task succeeds, the failover is completed.

FAQ

What are the differences between failover and decoupling in OCP?

• OCP performs the following additional checks in a failover:

  1. Check whether the primary and standby tenants have been added to OCP for management.
  2. Check whether the primary tenant is unavailable. This check prevents the existence of two primary tenants after the failover, to avoid upper-layer business errors.

• When you decouple a standby tenant from the primary tenant, OCP assumes that the primary tenant is available and therefore does not perform additional checks.