I have certain questions about replication in Artifactory Registry license for Docker images.
Looks like Artifactory Professional can use NFS to store the images and they have a dependency on database where they need to store the metadata.
Can two Artifactory Professional instances use the same NFS share for the images and share the same database to access the metadata? Will that be similar to emulate replication between the two Artifactory nodes? Or do they still need to do push or pull replication between the nodes?
What would be the ideal replication pattern if you have more than 2 nodes in the same data center with Artifactory Professional? Will a common NFS share and common database server help?
Unfortunately that's not how Artifactory works - sharing a common NFS and\or a database between multiple pro nodes is very risky and can cause a range of unwanted behaviour, data loss, locks etc.
Replication is meant to serve as means of having one instance mirror the other as a separate copy (i.e. for DR purposes), not by means of shared filesystem an database resources.
The requirements you raise however are answered completely by the High Availability version of Artifactory which allows (actually requires) you to share a filesystem and database between it's nodes, while the nodes themselves can be separated physically or logically.
As for your question - yes you will have to set up replication between your various nodes, they can't share these resources safely in the pro version.