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How to Avoid an Unnecessary Switchover

You can minimize the chance that a network problem causes a switchover between a functioning primary server and its backup. When disconnected from an LCA running on any host, SCS initiates a switchover for all applications running on the same host with the LCA. However, the disconnect can result from either long-term issues (such as the host being down or LCA terminating) or temporary issues (such as slowness of the network or a temporary network problem).

You can configure SCS to verify the connection status in a few seconds to confirm whether the connection issue is resolved. To do so, create the disconnect-switchover-timeout option in the general section on the Options tab of the SCS properties. Set the option value to any positive integer, which means the number of seconds, and depends on your typical network conditions. When SCS initiates a switchover process, it waits the interval you specified and checks the LCA connection:

  • If the problem has been temporary, the connection is restored and the applications on the LCA host are in Running status. In this case, SCS does not perform a switchover.
  • If the problem is serious, the LCA remains disconnected and the status of the applications on the LCA host is unknown. In this case, SCS proceeds with the switchover.
The disconnect-switchover-timeout option setting has no effect on a manual switchover, a switchover resulting from an alarm reaction, or a switchover resulting from service unavailability at the primary server.

Refer to the Framework Configuration Options Reference Manual for detailed option descriptions.

This page was last edited on September 5, 2014, at 17:52.


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