Amazon RDS for MariaDB instance read replica between regions

refer https://aws.amazon.com/premiumsupport/knowledge-center/rds-mysql-cross-region-replica/ for a better understanding,

Hello there,

RDS supports creating cross-region read replica for MariaDB across all regions. You can use AWS console to quickly provision a cross-region read replica. RDS uses asynchronous replication to replicate the changes from source database to the cross-region read replica database.

In case the primary database goes down, you can "promote" this cross-region read replica to a stand-alone instance and use this database's endpoint in your application. Please note that "promoting" operation is same for both in-region read replicas (source and replica in same region) and cross-region read replicas. Please note that once the read-replica is "promoted", it will no longer replicate the changes even if the previous primary database recovers.

In short, as mentioned in our documentation, the suggested "failure recovery" strategy is:

1. Promote the read replica.
2. Direct database traffic to the promoted DB instance.
3. Create a replacement read replica with the promoted DB instance as its source.

For more information, please refer the below links: RDS Cross region read replicas - https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_ReadRepl.html#USER_ReadRepl.XRgn Promoting a read-replica (applicable for both in-region and cross-region read replicas) - https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_ReadRepl.html#USER_ReadRepl.Promote How Amazon RDS does cross-Region replication - https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_ReadRepl.html#USER_ReadRepl.XRgn.Process