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Aurora read replica for RDS Postgres and long-term use



according to documentation, Aurora Read Replica for RDS Postgres is designed to be used as a migration step from RDS Postgres to Aurora. I was thinking of adding read replica to RDS and realized that Aurora could also be used.

Are there any downsides, if Aurora read-replica was used for long term read-replication of RDS Postgres without actually ever fully migrating to Aurora but keeping the RDS instance instead?

2 Answers

Note that when you create a Read Replica for the RDS PostgreSQL instance, its the native logical replication which comes into play. Meaning, the disadvantages of having a RDS Read Replica will stay even if you use Aurora PostgreSQL as a Read Replica.

But there are a couple of things which you might want to make a note of:

  • Evaluate if having an Aurora Read Replica for RDS PostgreSQL is making sense in terms of using Aurora features and if the price is justifiable to the business
  • There might be occasions when you might have to run Aurora PostgreSQL read replica to a different PostgreSQL version than its Primary i.e. RDS PostgreSQL instance as the Major upgrades might not be released on the same date
answered 18 days ago

Answering my own question; When Aurora is in read-replica mode for RDS, no furher reader instances can be added: "Creation of an Aurora Replica in a cluster which is already replicating from an RDS for PostgreSQL master is not allowed."

I guess full Aurora migration is needed by promoting the Aurora cluster and only after that, read replicas can be added.

answered 18 days ago

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