You cannot directly set hot standby nodes when you create a cluster. You can only enable the failover with hot standby feature for existing read-only nodes in your cluster.
Prerequisites
Only PolarDB for MySQL Cluster Edition 5.7 and 8.0 clusters support the failover with hot standby feature.
Precautions
- If the failover with hot standby feature is not enabled for read-only nodes, your services may be interrupted for about 20 to 30 seconds when failover occurs. Therefore, make sure that your applications can be automatically reconnected to the cluster. If the hot standby feature is enabled for read-only nodes, failover can be completed within 3 to 10 seconds.
- After the failover with hot standby feature is enabled for a read-only node, the node will no longer process read requests.
- The specifications of hot standby nodes must be the same as those of the primary node.
- The failover with hot standby feature cannot be enabled along with the in-memory column index feature. If a cluster contains a read-only column store node, you cannot enable the failover with hot standby feature on any read-only nodes in the cluster.