Adding Java Instances

Use

When the number of customer requests to the J2EE Engine is very big, you may need to resize your cluster by installing new Java instances.

You install new Java instances on different physical machines, thus adding more hardware resources to your system. In addition, this improves the failover capabilities of your system.

Prerequisites

You must have installed the basic components of the cluster (Central Services, at least one Java instance, and database).

Procedure

A Java instance consists of a Java dispatcher and one or more server processes. For more information, see Java Cluster Architecture in the Architecture Manual.

Using SAPinst, you can expand the cluster with new Java instances, which you can install on other hosts. For more information about the installation procedure, see SAP Service Marketplace at service.sap.com/instguides ® SAP NetWeaver ® Release 04 ®Installation.

 

Scaling the cluster by adding a Java instance

Guidelines

·        For applications that access the persistence layer frequently and require a lot of server processing, you can configure a cluster with less Java instances, each with more server processes.

·        We recommend that the Java cluster run behind a load balancer, such as SAP Web Dispatcher, which distributes the client requests between the Java instances. The Java dispatcher in each Java instance provides load balancing between the server processes. You do not need to configure the load balancing additionally. For more information, see Load Balancing of the SAP Web AS for J2EE Applications in the Architecture Manual.