Use a redundant Historian

You can configure the AVEVA Historian to have a "partner" AVEVA Historian that can be used as a hot backup if the primary Historian is not available. This is called a "redundant Historian" setup.

If AVEVA Application Server is configured to send data to the AVEVA Historian, the AppEngine automatically sends data to both the primary Historian and the specified partner. If one of the historians goes offline, the AppEngine stores the historized data until the Historian comes back online. After the connection is restored, the AppEngine forwards the data to the Historian that was offline.

The Historian Client automatically detects and selects the online Historian from the redundant pair.

The historians in a redundant setup are not intended to be a synchronized pair, where both the Historian configuration and data are fully and automatically synchronized. It is up to you to make sure that the two historians are symmetrical and synchronized. The following recommendations are examples of actions you should take to keep the pair synchronized, or else incoming data is not stored as previously described.

• If you make configuration changes for one Historian, be sure to perform the same actions on the partner.

• If you import a CSV file on one Historian, you will need to repeat the import on the partner.

• If you add or update data to one Historian using SQL or the Historian SDK, you will need to repeat the action on the partner.

To specify a Historian partner:

1. In the Operations Control Management Console, expand Historian Group, expand the server, and then expand Configuration Editor.

2. Expand System Configuration and then click Parameters. A list of all system parameters displays in the details pane.

3. Double-click the Historian Partner system parameter. The System Parameter Properties dialog box appears.

4. In the Value box, type the computer name of the partner Historian. You can use either the host name, fully qualified name, or an IP address. Leading backslashes are optional.

   Note: In network environments where AppEngine and Historian Client computers on different subnets must access the partner, be careful to use a name or IP address that can be correctly resolved from all of those network locations and not just between the Historian servers themselves.

5. Click OK.