Historian Data Mirroring
If you have purchased an Enterprise-level license for Historian and your license entitlement includes mirror nodes, you have the option of setting up to three mirrors (primary server + two mirrors).
Historian Data Mirroring provides continuous data read and write functionality. In a typical data mirroring scenario one server acts as a primary server to which the clients connect.
To create a mirror, you add mirror nodes and establish a data mirroring session relationship between the server instances. All communication goes through the Client Manager, and each Client Manager knows about the others.
Mirrors must be set up in a single domain.