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01/18/2021
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I have a query regarding non-transparent server redundancy, in particular its Hot mode.
The scenario is as follows:
A client has 2 servers, A and B. A is the active server. The client has made a Set PublishingMode with publishingEnabled = TRUE service request on server A, to enable notifications from the server.
The connection to server A fails, so the client fails over to server B. The client makes a Set PublishingMode with publishingEnabled = TRUE service request on server B, to enable notifications from server B.
The connection to server A then recovers. But server B remains the active server. Does server A still send notifications to the client?
If server A still sends notifications to the client after its connection to the client recovers, I assume that the client should make a Set PublishingMode with publishingEnabled = FALSE service request, to disable notifications from server A. (We only want notifications from one server at a time.) Is my assumption correct? Or does the server itself revert to notifications disabled when its connection to the client recovers?
05/30/2017
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If Server A goes down the Client needs to go through the reconnect sequence described in
https://reference.opcfoundatio.....5/docs/6.7
If it is able to recover with ActivateSession then the updates from Server A will still be published and the Client needs to set PublishingMode = False.
If the Client has to re-create the subscriptions from scratch it would create new subscriptions with PublishingMode = False since Server A is no longer active.
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