Is creating a Read Replica of another Read Replica supported?
Only in certain regions
Only with MSSQL based RDS
Only for Oracle RDS types
Q: Can I create a Read Replica of another Read Replica?
Amazon RDS for MySQL: You can create a second-tier Read Replica from an existing firsttier Read Replica. By creating a second-tier Read Replica, you may be able to move some of
the replication load from the master database instance to a first-tier Read Replica. Please
note that a second-tier Read Replica may lag further behind the master because of additional
replication latency introduced as transactions are replicated from the master to the first tier
replica and then to the second-tier replica.
Amazon RDS for PostgreSQL: Read Replicas of Read Replicas are not currently supported.