Oracle ADF is used to build large enterprise application. And if you want to have your application to run on high availabilty then you should understand what is High Availability (HA).
What is High Availability –
High availability refers to the ability of users to access a system without loss of service. Deploying a high availability system minimizes the time when the system is down, or unavailable and maximizes the time when it is running, or available. This section provides an overview of high availability from a problem-solution perspective. With HA , even for new deployment you will never have down time.
Normally in large enterprise application , you don’t want your system to be down..Application deployed in cluster environment. If one of the server down then the user session should replicate to another cluster . Now , we have Oracle HTTP Server (OHS) or Apache plugin is to used to get single URL and manage internally to replicate the session and send request if one of cluster is fail.
How a web server handle request
Cluster- Group of managed server running to provide scalability and reliability. In this multiple wls instance simultaneously and working together.Cluster is part of WLS domain . A domain can have multiple cluster. Read the complete article here.
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