I wonder if you can help. I need to replicate a Postgres 8.4 database (master-slave style) from an on-premise server to an RDS instance on AWS running Postgres 9.x. I've read that Postgres > 9.0 has a nice replication mechanism, but before that tools like Slony ruled. The problem I'm seeing with Slony is that it seems to need a process to be running on the target database which is a problem for me because RDS is fully managed.

Can anybody suggest a path to make this happen? I'd like to avoid downtime of the source 8.4 database whilst taking a dump and then importing it on the other side.

Thanks in advance for you help!

1 Answer 1


I think your best approach is using the Database Migration Service AWS launched past year.


This service is specifically designed for your use case. It is "simply" a managed appliance running on top of an EC2 instance in your VPC. Once deployed and assuming no connectivity problems, you submit the details for source and target databases, configure some transformations if needed and then the service manages the initial load and further replication, in an asynchronous way.

I have used it already both for OnPremises-to-AWS and RDS-to-RDS for cloud migrations and engine upgrades, and achieved nearly zero downtime in all cases. It works just great.

  • Thanks! The problem was the Postgres version because it's non trivial to move from 8.4 to 9.x even with the AWS DMS. We ended up doing it the old fashioned way with a couple of dumps and insertions on the other side. Mar 12, 2017 at 12:18

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