Behaviour of Read Replicas in multi AZ Deployment

Question

I have some question with respect to using read replicas in Amazon RDS Multi-AZ Deployments mechanism.

my architecture:- Normally in case of simple muti az deployment we have master db in one az with standby db in another az but here I in my situation there is a master database in one az and read replica in another az which is like a standby database another az( hope that makes sense).

Multi az mechanism provides:-

1. sync replication between main db and stand-by DB.
2. automatic failover.
3. single dns name for automatic failover.

read replicas provide:-

1. async replication between main db and read replica.
2. needs to be promoted manually in case of failover.
3. connection string needs to be updated on the application part hence a different connection string.

So when we use read replicas under multi az mechanism what will be the status of replication ( sync or async), automatic failover or manual promotion, and what about the connection string single DNS or different ( as in read replica)

Answer 1

If I understand correctly, you have a Multi-AZ instance together with a read-replica.

In case of automatic failover, the read-replica should continue replicating from the standby DB. Nothing is required on your side, except for refreshing your DNS records before trying to access the master.

In case of manual promotion - i.e. turning the read-replica into your master - you will of course have to update your connection string manually, because the end-point will have changed.