I've got a 2.3TB Database running at Rackspace... We'll be migrating it to RDS PostgreSQL 9.5 very soon...
... a EC2 Instance with full replica from prod (rackspace) has already been settled up at Amazon and it's working fine... (DMS will use that instance)...
As I've never used DMS, I just don't know how long it will take to migrate from EC2 Instance(Postgres 9.2) to RDS(Postgres 9.5)... can you guys give me some tips here? If anyone has used that would be great sharing the experience....
I don't know the answer for this but...
Also, will I have to migrate from Pgsql 9.2 to 9.3? Or I can to straight to 9.5?
This, I know :) You can go straight to 9.5.
IIRC the DMS doesn't actually support 9.2, it requires 9.4 or newer I believe. (You should double check that, my information might be old)
So you would have to start by upgrading your standalone cluster to 9.4 or 9.5 (PostgreSQL itself has no problem going directly to 9.5), and then use DMS to move it to RDS.