Sun Java System Application Server 9.1 Deployment Planning Guide

Common Requirements

This section describes the requirements that are common to both topologies:

General Requirements

Both topologies must meet the following general requirements:

HADB Nodes and Machines

Each DRU contains a complete copy of the data in HADB and can continue servicing requests if the other DRU becomes unavailable. However, if a node in one DRU and its mirror in another DRU fail at the same time, some portion of data is lost. For this reason, it is important that the system is not set up so that both DRUs can be affected by a single failure such as a power failure or disk failure.

Note –

Each DRU must run on a completely independent, redundant system.

Follow these guidelines when setting up the HADB nodes and machines:

Caution – Caution –

Do not run nodes from different DRUs on the same machine. If you must run nodes from different DRUs on the same machine, ensure that the machine can handle any single point of failure (for failures related to disk, memory, CPU, power, operating system crashes, and so on).

Load Balancer Configuration

Both the topologies have Application Server instances in a cluster. These instances persist session information to the HADB. Configure the load balancer to include configuration information for all the Application Server instances in the cluster.

For more information on setting up a cluster and adding Application Server instances to clusters, see Chapter 5, Using Application Server Clusters, in Sun Java System Application Server 9.1 High Availability Administration Guide.