Sun Java System Reference Configuration Series: Portal Service on Application Server Cluster

Modularity in the Deployment Architecture

The reference configuration deployment architecture is based on a Service Delivery Network Architecture (SDNA) approach, in which individual services within a solution are modularized (see The result is a deployment architecture consisting of four independent service modules: SRA Gateway, portal, Access Manager, and directory.

In accordance with SDNA principles, each service module in the reference configuration independently implements its own level of availability, security, scalability, and serviceability. The overall solution can therefore be easily deployed, secured, maintained, and upgraded. An explanation of how the reference configuration's modular architecture facilitates quality-of-service objectives is provided in subsequent sections of this chapter.

The service modules that make up the reference configuration, shown in Figure 2–2, have the following common SDNA characteristics:

While the modular architecture depicted in Figure 2–2 has many advantages, as described in subsequent sections of this chapter, alternative approaches in common practice do exist. The drawbacks of two such alternatives, which are not supported by this reference configuration, are discussed below.

Not Supported: Portal Server and Access Manager Combined

In some situations, the modular architecture of Figure 2–2 might result in lower resource utilization than could be achieved by combining components on the same computer and running them in the same web container. In fact, many deployment architects have traditionally deployed Portal Server and Access Manager in the same web container in an effort to maximize resource utilization and reduce network traffic in updating Access Manager session information. However, such designs cannot realize the availability, security, scalability, and serviceability benefits of SDNA modularity, which generally outweigh the drawbacks.

Not Supported: Access Manager Internal Configuration for Multiple Directory Server Instances

Access Manager supports, by way of post-installation configuration, multiple LDAP directories for each Access Manger service. In this way, Access Manager can detect failure of a primary Directory Server instance and fail over to an standby instance. This built-in mechanism has several drawbacks:

By contrast, the modular architecture of Fig 2-2 has the following advantages:

Note –

In the multimaster replication approach of Figure 2-2, write operations are synchromized between directory instances. In environments with many write operations, the overhead of the multimaster replication process can slow down Directory Server processing of client requests. In these situations, the best approach is to direct all write operations to a single master by placing a Directory Proxy Server instance in front of each Directory Server instance. Such situations are not common in portal service deployments, so the reference configuration does not include Directory Proxy Server.