The manager controls the other processes, including the start and stop functions.
The extract process pulls data out of a database and stores it either locally or remotely. If the extract process has to store the data locally, it does so by writing it to a file. If the extract process has to store the data remotely, it communicates with a remote server process and gets the server to store the data in files. The files that contain the data are called trails.
A replicat process picks up the information from a trail and stores it into a target database.
A healthy Oracle GoldenGate instance has at least the manager up and running. Although such an instance is valid, it cannot process any data. A fully working Oracle GoldenGate instance has at least an extract process or a replicat process up and running. You need at least two Oracle GoldenGate instances; one to serve as a sender and the other to serve as the receiver. The two Oracle GoldenGate instances can be configured either on the same cluster or on two different clusters. Also, it is valid to have one instance in a cluster and the other instance unclustered.
The Oracle GoldenGate instance and the underlying components have data services that protect them in an Oracle Solaris Cluster configuration, as described in the following table.