NetScaler downStateFlush Parameter Explained
Article ID: CTX140147
Updated On:
Description
This article explains the behavior with the ‘-downStateFlush’ parameter as it relates to the instance of a NetScaler monitor marking a service down. It also explains what the client connected to that service could expect.
downStateFlush
The parameter ‘-downStateFlush’ is set to ON by default for any service. If a monitor probe fails the number of configured retries, the monitor marks the service DOWN. At the time the service is marked DOWN, one of the two outcomes can be expected by the client depending on the setting of the downStateFlush parameter as follows:-
If downStateFlush is set to ON, any established connections are freed by a zombie cleanup process. This process generates a reset with a window size of 9301 sent from the VIP to the client immediately terminating that connection.
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If downStateFlush is set to OFF, connections will not reset, but instead might become unresponsive or get a response depending on what state the back-end server is exactly in. That is, it might be DOWN from the monitoring criteria perspective, but still alive and capable of sending a response.
Issue/Introduction
