Deleting RDS Read Replicas

Question

I recently had a RDS read replica crash, so needed to spin up a new read replica.

Now I have both read replicas there.

I want to delete the one that failed.

Is it just a case of terminating it? Does it have any affect on the master or the other read replica?

Have not ever had to do this before, so want to be sure I am doing this the right way

Answer 1

This should be a perfectly safe operation, but taking a last-minute snapshot of your master (or even the other replica, if it's on-line, replicating, and synched) wouldn't hurt.

In MySQL replication, the connection between master and replica is initiated from the replica ("slave") server side -- if a replica goes offline, the master server just closes the connection and goes about its business; there is essentially no risk to the master from a replica disappearing, even at random.

Specifically, in RDS, replicas seem fairly clearly to be designed to be disposable, and RDS also provides the ability to "promote" a replica -- which is not a promotion to being "the" master (replacing the existing one), but rather a promotion to being "a" master, an independent standalone system of its own, fully disconnected from its former relationship with its former master.

If it made you more comfortable, you could "promote" the replica first, and then delete it once you see that process complete, though simply deleting the replica should be harmless.

http://aws.amazon.com/about-aws/whats-new/2012/10/11/amazon-rds-mysql-rr-promotion/