The Storage Team Blog about file services and storage features in Windows and Windows Server.
When you configure DFS Replication, you select the primary member that has the most up-to-date files that you want replicated to other members. The primary member's files will always win the conflict resolution that occurs when the receiving members have files that are older or newer compared to the same files on the primary member. After the initialization of the replicated folder, the "primary member" designation is removed. That member is then treated like any other member and its files are no longer considered authoritative over other members that have completed initial replication.
There might be occasions when you want to know which member was set as primary…but you can’t remember the member you selected. According to our DFS Replication guru Rob Post, you can look for event 4112 in the DFS Replication event log on all 3 servers. The one that has this event was set to primary.