Can I change istance type of an RDS read replica without breaking replication?

Question

Basically we have currently this situation:

• RDS Master in eu-west-1 (db.t2.small)
• RDS Replica in us-east-1 (db.t2.small)
• RDS Replica in us-west-1 (db.t2.small)

We want to change the instance type of the two replicas to db.t2.medium while keeping the one of the master at db.t2.small.

I know when you change the instance type the RDS instance will go down until modification is done. What I would like to know upfront is if replication will break after the replica will come back up or it will recover the missing data automatically without troubles ?

Thank you very much in advance for your help :)

Answer 1

It will recover the missing data, or "catch up" with replication once the read-replica server comes back up. Another method would be to add a new t2.medium read-replica to your database cluster, and once it is up you could delete the old t2.small read-replica.