while this is a very high level question, it is actually where should start from .
I recommend you to check the cloud documentation to get familiar with OCI architecture, you can start here with some basics.
As such, here is some generic guidance on how and where to start from:
1) you can follow exact steps as in an on-premise environment ( if data to migrate is too large and not subject of copy over the internet consider also transfering data )
3) Object Storage; once you will get familiar with OCI concepts and architecure to sync to another AD is depending on your scenarios, see what resources are available to all ADs and only in some AD, for example block volumes backups can b restored as new volumes to any AD within the same region.
Hope that helps you.
So on IaaS all will be manual. Install & Configure PostgreSQL on OEL, Migrate the data using data transfer utility.
Re: 2& 3) Can I use 3rd party solutions for Backup/Recovery and DR sync for DB. ?
Wanted to ask will BMC be a good choice or VM shapes..?
Not really, is entirely depending on you and your stack.
You can setup a stack using bitnami for example and customize it afterwards.
Use data transfer utility only if you cannot upload the data over the Internet directly into your machine in the cloud.
Check the cloud marketplace for 3rd party tools, there are 3rd party tools ( you can use the search option combined with the relevant Product = OCI)
BMC Vs VM ? BMC is always a good choice , i.e. a physical server dedicated to you, ideally if your apps are IO intensive or big data related, plus access to NVMe SSDs ... see more here about the BM shapes.
If not your case, or too early for you to decide, start with a VM shape.
Thanks for the prompt reply...
1) Bitnami supports postgres 10.3 version. So any other version have to transfer the binaries and install.
2 & 3) Products are there. Need to evaluate.
If need to do manual, can I use the same on-prem methods of postgres replication methods. ?
Can the block storage be replicated across AD's
Yes, as mentioned in my 1st reply at 3), for example if you go by block storage replication, then the backup of those will be available across ADs.