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Amit585731's avatar
Amit585731
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Feb 17, 2016

GTM failover

Hi Experts,

 

In our environment we are using DNS box which is caching response from GTM (caching is done for 30 sec) and then forward query to VIP on ltm A. We have 2 ltm behind GTM i.e. ltm A and ltm B. Once VIP on ltm A fails it should automatically fails to ltm B but during this case we are seeing this is not happening. Once VIP on ltm A fails then users have to close the browser and reopen the browser to connect to VIP. And thus we see new connection going on ltm B. Until the browser is closed the session continues to go on ltm A even if we are using ctrl + f5.

 

The application team requirement here is that failover should be transparent.

 

Please suggest.

 

Thanks.

 

application delivery
gtm
LTM

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  • MVA's avatar
    MVA
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    Feb 17, 2016

    My first thought is the application on the servers need to be session aware, meaning if a user session starts on one the others know about it and can pick it up, if needed. This would be required for the transparent requirement. Back to your question, I would troubleshoot with nslookup/dig against the WideIP before and after failover to confirm the client is seeing the IP address change. With dig you'll also see the ttl timeout and it should decrement. If that's true then I would look at the browser traffic to see if the app is somehow sending the client to an LTM pool member. I've seen this work successfully with VMWare VDI - not sure about the transparent part, but failover works.