This article describes how to force connections to the backup virtual server immediately during a planned service outage.

Background

During a planned service outage of a Load Balancing virtual server, the service of the virtual server are disabled with a timeout to allow the existing connections to close.

This action assumes that the Down State Flush option is not enabled. Any new connections to the virtual server cannot be addressed immediately even if  the backup virtual server is configured. 

Instructions

Note: The backup virtual server takes the connection requests immediately after the services of the load balancing server disables with a wait time.
To configure Spillover on a load balancing virtual server, complete the following procedure:

1. Select Advanced in the Properties tab of the load balancing virtual server.

2. Change the Spillover method to HEALTH.

3. Set the Spillover Threshold to 99 percent.
   Note: This threshold indicates that as soon as the service health of the virtual server is under 100 percent (such as when the service members are DISABLED), then the connections for the load balancing virtual server are sent to the configured backup virtual server.

When you try to connect after you disable the service, the connection request must reach the backup virtual server.

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