Siemens SIMATIC PCS 7 Function Manual page 197

During the steps involved in Phase 1, your system continues to work with only one server. The
system remains controllable from the OS clients that have not yet been updated. If this server
fails, the automation system can no longer be controlled.
Perform the steps without extended interruptions because the redundancy is not available
during the update.
Initial situation before phase 1
● Server_1 is master server.
● Server_2 is standby server.
● Client_1 is connected to Server_1.
● Client_2 is connected to Server_2 because this server is configured as its preferred server.
Requirements
● The PCS 7 project you are updating has already been updated on the ES.
● When using an archive server:
Procedure - Phase 1
Note that you will need to work alternately on Server_1 and Server_2.
Phase 1 / 1. Server_2: Deactivate and exit WinCC
● Deactivate WinCC Runtime and exit WinCC on the standby Server_2.
Phase 1 / 2. Server_2: Backup of the PCS 7 project; backup of the operating system and of
the PCS 7 software installation
● Back up your previous operating system, the previous PCS 7 software installation and your
Phase 1 / 3. Server_2: Installation or update of the operating system, PCS 7 Installation "OS
server"
Fault-tolerant Process Control Systems (V8.0)
Function Manual, 03/2012, A5E02779471-02
CAUTION
– If you are using "StoragePlus", ensure that the archive server is closed.
We recommend that you switch to an external archive server.
– Synchronization of the archive must be complete to ensure that the process data (RT
data) are consistent.
The system reacts as follows:
– Client_1 remains interconnected with Server_1.
– Client_2, which has Server_2 configured as the preferred server, changes over to
Server_1.
– Server_1 detects a failure due to Server_2 being deactivated. If you have configured
system messages, Server_1 generates a process control message to this effect.
current PCS 7 project as a fallback strategy.
Failure, Switchover and Return of Fault-tolerant Components
6.10 Guidelines for updating a redundant OS in runtime
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