Specifications

14 – Configuring and Monitoring a Redundant Server System
326 R400
Failover of a Redundant Server System
The backup server takes over from the primary if:
• The primary server hardware fails and the backup cannot communicate with
it
• All network links between the primary and backup server are broken
• The primary loses C200 communications because of a non-recoverable
failure in its C200 communications subsystem
• A user does a manual failover (see “Manually Failing Over a Redundant
Server System” on page 327)
The primary server can be configured to restart (with the backup server
becoming primary) if one of the following tasks fails:
• timer (controls timing of all PlantScape Server tasks)
• scanx (controls the SCADA scanning subsystem)
• daqmgr (controls the delivery of SCADA acquisition requests to the
appropriate SCADA driver)
The backup server does not take over from the primary if a SCADA channel fails.
plscpcg.book Page 326 Monday, May 28, 2001 10:11 AM