How Do You Achieve Cluster Session Replication?
Answer: There are two types of Session Replication in Weblogic Cluster.
1. In-Memory replication
2. DB based Session Replication
Sessions replication can be done using memory which can be accessed very fast.
for example, if you see the below line in weblogic.xml
replicate-if-clustered>true This means in-memory replication is enabled if the application is deployed on a cluster.
In-Memory Replication: The primary server process the request and choose another server to keep the backup of https session details.
So, the secondary server will only keep the backup, not process the request. The information on (Replication) will be sent back to the browser (cookies). In case, the primary server goes down, the LB ( Load balancer) will direct to the secondary server , based upon cookies to process the request from the point where primary server stopped. It is called In-Memory Replication.
DB-based Replication: Instead of storing https session backup in other managed servers, it can be stored in DB. Now, the Load Balancer can direct any available server to continue the request, if the primary server goes down.
It is called DB based Replication.