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We had 2 managed servers sitting behind a Citrix Netscaler loadabalncer with sticky session enabled, so a request will be forwarded to the same managed server.

Now we configured a coherence*web cluster with 2 managed servers and a Citrix Netscaler as load balancer sitting in the front. How do we call the coherence cluster from the loadbalancer without calling the managed servers? Is there any IP address for the coherence cluster that we need to call from the netscaler or how to call the cluster without calling individual servers?

Thanks a lot.

Arun
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  • How are you accessing the coherence cluster? – Hououin Kyouma Dec 06 '14 at 16:12
  • I am not sure how to access the coherence cluster, that is my question. When coherence was not used, nescaler was configured to individual server's IP address with sticky session enabled. I am not how to have netscaler access the coherence server without IP. – Arun Dec 06 '14 at 16:51
  • So when you run a coherence server, you need not use the load balancer. Coherence ditributes objects and hence there is no need for it. To access the coherence server, you must run the coherence.sh or coherence.bat and specify in the coherence IP and port as mentioned in the coherence config. – Hououin Kyouma Dec 06 '14 at 18:09
  • I understand that, but let's say my website is www.coolweb.com. A request comes to the site and the DNS should redirect the request to a server. Which server Ip will it redirect to? If it redirects to one of the two managed servers IP, then there is no point in having a coherence Web for Session management. Correct me if I am wrong. I believe that the DNS should redirect the request to a server (which one???) and that server should load balance and send request to one of the managed servers. – Arun Dec 07 '14 at 05:39
  • Arun - load balancing simply makes sure that the requests get spread across servers. Coherence makes sure that the sessions are available to all of those servers, even if stickiness fails or a server fails or if you add a new server etc. – cpurdy Feb 04 '15 at 01:33

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You keep the same config that you had before for load-balancing to the web or application servers.

Coherence*Web makes sure that the data in the sessions will be shared between those servers (even if you add and remove servers dynamically!), and will not be lost if one server dies.

cpurdy
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