Selecting A Preferred Server - Siemens SIMATIC PCS 7 Configuration Manual

Configuring OS functions
10.1 Project settings
Note
The server data includes the computer name of the ES from which the server data is to be
downloaded automatically. If the ES cannot be reached, the OS client attempts to download
the server data directly from the server when runtime is restarted.
If the project is moved to another path or to another ES (another computer name), the server
data must be regenerated (manually or by compiling the OS) and reassigned to the OS client
projects.
10.1.2

Selecting a preferred server

Introduction
In order to achieve even utilization of a redundant server pair and constant operability, even
during a switchover to the redundancy partner, you should assign one section of the OS clients
to the master server and another to the standby server.
A "preferred server" is an OS server in the redundant OS server pair that the OS client connects
to preferentially. The OS client receives the data from there as long as this OS server is
available.
This requires a consistent connection configuration on both OS servers and no errors
(redundancy) at the PCS 7 end. If the connection configuration is inconsistent or if there are
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Compendium Part A - Configuration Guidelines (V8.2)
Configuration Manual, 08/2016, A5E38166869-AA