When the primary server of a redundant pair fails, the secondary server goes from standby to active mode to insure that all essential areas in the project continue to operate.
Areas include:
Device communications and point
management.
Alarm management.
User logons.
Runtime interfaces.
Device Communications and Point Management
Device Communications on the secondary server begins actively polling for data and passes point data to the Point Manager on the secondary server, which now becomes the primary Point Manager. Any viewer process that was connected to the original primary Point Manager will automatically switch over to the new primary Point Manager, which will now assume all supervisory and control functions.
Note: Between the time that the primary
server is lost and before the secondary server takes over, users
may notice an interruption in system performance. During this time,
point values will not be updated, setpoints and alarm
acknowledgments will not complete, and users will not be able to
log on or off.
Alarm Management
The Alarm Manager on the secondary server becomes the primary Alarm Manager. No alarm data is lost because the Alarm Manager on the primary server continually updated the alarm list for the Alarm Manager on the secondary server. The new primary Alarm Manager will now process all alarm updates and provide alarm information to all interested processes.
User Logons
The User Registration process on the secondary server becomes the primary User Registration process. No user registration data is lost because User Registration on the primary server continually updated the user list for User Registration on the secondary server. The new primary User Registration will now process all user logins and logouts and provide information on user views.
Runtime Interfaces
When the primary server fails, all CimView, Alarm Viewer and Point Control Panel sessions running on that server are lost.
CIMPLICITY user interface accessed
from console on the primary server.
When the primary server fails, this console is no longer usable. The user will have to move to the console on the secondary server, log in, and access the CIMPLICITY user interface from there.
CIMPLICITY user interface accessed
from a Viewer.
The user interfaces will fail over to the new master.
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Primary server failure. |
