Existing RSA IGL is deployed in single instance, do we have any recommendation document or design document which can be used for separating database (RSA supplied) and AFX server with existing running instance.
While I'm not aware of a specific document that provides guidance on the exact steps for your scenario/use-case, it should be doable by following the high level steps below. Make sure to validate those steps in your test environment before doing the same in production. You can also engage RSA Professional Services for assistance with providing you the exact steps based on your requirements.
Once the IGL application server with restored database is confirmed to be working, download the AFX server archive/zip from the UI and install the AFX server on a remote host. Follow steps in the RSA Identity Governance and Lifecycle 7.2.1 Installation Guide.
While I'm not aware of a specific document that provides guidance on the exact steps for your scenario/use-case, it should be doable by following the high level steps below. Make sure to validate those steps in your test environment before doing the same in production. You can also engage RSA Professional Services for assistance with providing you the exact steps based on your requirements.