When Does an Active/Standby Switchover Occur?
An active/standby switchover may occur in the following scenarios:
l An active/standby switchover operation is initiated on the console.
l An active/standby switchover will be triggered when the active node of an active/standby instance fails.
For example, if commands (such as keys) that consume a lot of resources are used, the CPU usage will surge, triggering an active/standby switchover.
l If you restart an active/standby instance on the console, an active/standby switchover will be triggered.
How Does Active/Standby Switchover Affect Services?
If a fault occurs in an active/standby or cluster instance, a failover is triggered automatically. Services may be interrupted for less than half a minute during exception detection and failover.
Does the Client Need to Switch the Connection Address After an Active/Standby Switchover?
No. If the active node fails or an active/standby switchover is performed, the standby node will be promoted to active and take the original virtual IP address.
What Is the Redis Active/Standby Synchronization Mechanism?
DCS Redis standard version active/standby and cluster version active/standby instances support the deployment of HA instances. You can choose to deploy instances in a single AZ or multiple AZs. When a tenant deploys an instance across multiple AZs, the Redis instance actively establishes and maintains Redis synchronous replication. In the event of an active node fault, the DCS instance automatically promotes the standby node to the active node to achieve HA. If the tenant mostly uses the DCS instance to read the business data, they can choose an active/standby cluster instance, because the DCS instance actively maintains data synchronization and replication between the active node and the standby node.