In a clustered deployment, EAServer replicates user session data stored in HTTP sessions so that the same data is available on other servers in the cluster. Replication can use a remote database server or in-memory storage.
If using in-memory replication, EAServer replicates data between mirror pairs, that is, a pair of servers configured to share the same user session. In-memory replication can perform better than using a database, but requires more memory on each server. Specify a cache size to constrain the memory required by the cache, and specify a timeout to free up memory used by idle sessions. To set these parameters, follow the instructions in “Deploying Web applications to a cluster” in Chapter 7, “Load Balancing, Failover, and Component Availability,” in the EAServer System Administration Guide.
If using database replication, all servers in the cluster store session data in a remote database. This mechanism can perform slower than in-memory replication, but requires less memory. Also, EAServer can share a client’s session data on more than two servers. If using this technique:
Tune the connection cache settings as described in “Connection cache settings”.
Make sure the table used is indexed. For information on creating the database table, see “Table schema for binary storage” in Chapter 29, “Configuring Persistence Mechanisms,” in the EAServer Programmer’s Guide.
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