Creates a Neptune global database spread across multiple Amazon Regions. The global database contains a single primary cluster with read-write capability, and read-only secondary clusters that receive data from the primary cluster through high-speed replication performed by the Neptune storage subsystem.

You can create a global database that is initially empty, and then add a primary cluster and secondary clusters to it, or you can specify an existing Neptune cluster during the create operation to become the primary cluster of the global database.