opHA introduces the concept of a Primary & multiple Poller servers and a message bus:

The Primary is the server that keeps the information of all the pollers and it is where we can read all the information from. The Consumer (ophad running on Primary) reads data continuously off the message bus and stores it in the database
The Pollers, collect their own data, and send that information to the Primary when it is requested.Producer (ophad running on Pollers) has a change stream setup for the collections and recieves update from the database if there is any. This change stream data is pushed onto the message bus.

Here are terms used in this project together with their meanings.

Term	Meaning
Main Primary	server instance running opHA with role = 'primary_master'
Secondary Primary	server instance running opHA with role = 'master'. Also referred to as just 'primary'.
Peer	server instance running opHA with role = 'poller' or 'mirror'. It can optionally be of type 'streaming' which means that it is linked to an ophad instance.
Poller	server instance running opHA with role = 'poller'
Mirror	server instance running opHA with role = 'mirror'. It is paired with a poller and polls the same devices as that poller, however its data is not sync'd with primary unless the poller is offline.
Producer	an instance of the ophad process running in 'producer' mode (as per configuration). This will typically be running on the same server instances as the primary.
Consumer	an instance of the ophad process running in 'consumer' mode (as per configuration). This will typically be running on the same server instance as the poller (or mirror)

Versions Compared

Key