2
Concepts for Administrators

This chapter introduces concepts for designing, installing, and managing an application server.

It contains the following topics:

• Introduction

• Application Server Installations

• The Oracle9iAS Infrastructure

• Customer Databases

• Sample Application Server Enterprises

• Designing an Application Server Enterprise

• Installing an Application Server Enterprise

• Managing an Application Server Enterprise

• Reconfiguring an Application Server Enterprise

Introduction

Oracle9i Application Server uses a three-tiered architecture as shown in Figure 2-1.

Figure 2-1 Oracle9iAS Three-Tiered Architecture

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• The client tier contains different types of clients including Web browsers, mobile and wireless devices, Web Services, and back-office applications. Clients send requests to the application server tier using a variety of physical networks and protocols.

• The application server tier, or middle tier, contains the Oracle9iAS solutions that provide industry-standard Web applications and services. The application server tier processes requests from the client tier. It may access or update data in the database tier to complete a request.

• The database tier consists of databases that contain data, metadata, and business logic.

To clients, the application server tier and database tier appear to be a single, ever-present entity that efficiently processes requests. In reality, the application server tier and database tier may contain many entities working together to create a seamless platform, as shown in Figure 2-2. There may be one installation of Oracle9iAS solutions, called an application server installation, on a single host, or multiple application server installations on multiple hosts. There may be a central source of user, security, and configuration information called an infrastructure. There may be databases in the database tier, called customer databases, that collect and process information for Oracle9iAS solutions.

Figure 2-2 Application Server Enterprise in the Three-Tiered Architecture

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This collection of application server installations, infrastructures, and customer databases is called an application server enterprise. The application server enterprise is the framework within which you design, install, and manage all of the features and solutions Oracle9i Application Server offers.

This chapter introduces the concepts and practices for managing an application server enterprise.

Application Server Installations

An application server installation (also called a middle-tier application server installation or middle-tier installation) is a set of Oracle9iAS solutions installed into a single Oracle home. The Oracle9iAS solutions in an application server installation are called components. Your enterprise can have one or more application server installations, residing on one host or distributed across multiple hosts.

Application Server Install Types

There are four types of application server installations, or install types, each providing a set of components. The install types are ordered, in that each contains all of the components in the previous install type, plus additional components. The install types are:

• J2EE and Web Cache: Provides a basic Web server that enables you to develop and deploy Java 2 Enterprise Edition (J2EE) applications, use J2EE and Simple Object Access Protocol (SOAP) based Web services, accelerate Web site performance, and manage your application server with a Web-based tool.

• Portal and Wireless: Enables you to deploy enterprise portals and wireless applications. Includes all components available in the J2EE and Web Cache install type.

• Business Intelligence and Forms: Enables you to analyze clickstream data, personalize applications, perform data analysis, generate Web-based reports, create Discoverer public connections, configure Discoverer viewer and Discoverer Portlet Provider, and use Forms-based applications. Includes all components available in the Portal and Wireless install type.

• Unified Messaging: Enables you to integrate different types of messages into a single framework. Includes all of the components available in the Business Intelligence and Forms install type.

Table 2-1, "Oracle9iAS Install Types" shows which components are provided in each install type.

Table 2-1 Oracle9iAS Install Types  

Component	J2EE and Web Cache	Portal and Wireless	Business Intelligence and Forms	Unified Messaging
Oracle HTTP ServerFoot 1	YES	YES	YES	YES
Oracle9iAS Containers for J2EE	YES	YES	YES	YES
Oracle9iAS Web Cache	YES	YES	YES	YES
Oracle Enterprise Manager Web site	YES	YES	YES	YES
Oracle9iAS PortalFoot 2	no	YES	YES	YES
Oracle9iAS Wireless	no	YES	YES	YES
Oracle9iAS DiscovererFoot 3	no	no	YES	YES
Oracle9iAS Reports Services	no	no	YES	YES
Oracle9iAS Clickstream Intelligence	no	no	YES	YES
Oracle9iAS Forms Services	no	no	YES	YES
Oracle9iAS Personalization	no	no	YES	YES
Oracle9iAS Unified Messaging	no	no	no	YES

1 Oracle HTTP Server installs the following Oracle mods: mod_oc4j, mod_ossl, mod_proxy, DMS, FastCGI, HiAv Infrastructure, Oracle9iAS Java Object Caching, SOAP, DBI/DBD, Clickstream Collector Agent. 2 Oracle9iAS Portal installs Oracle Ultra Search and Oracle9i Syndication Server. 3 Oracle9iAS Discoverer installs Discoverer Viewer, Discoverer Plus, and Discoverer Portlet Provider.

About Configuring Components

An application server installation contains the files necessary to support all of its components, but you do not have to configure all components.

Note: The term configure can have one of two meanings, depending on the status of a component. The first time a component is configured, it is initially setup to run. After that, to configure a component means to tune component parameters. This chapter uses the term configure to mean the initial setup of a component.

The following components are automatically configured:

• Oracle HTTP Server (automatically configured in all install types)

• Oracle9iAS Containers for J2EE (automatically configured in all install types)

• Oracle9iAS Web Cache (automatically configured in Portal and Wireless, Business Intelligence and Forms, and Unified Messaging install types; optional in the J2EE and Web Cache install type)

Other components can be configured at install time or any time after installation. Because some components depend on each other, there are a few guidelines for configuring them, as described in Table 2-2.

Table 2-2 Guidelines for Configuring Components  

If you configure:	You should configure:
Oracle9iAS Clickstream Intelligence	Oracle9iAS Discoverer Oracle9iAS Portal
Oracle9iAS Discoverer	Oracle9iAS Portal
Oracle9iAS Forms Services	Oracle Management Server Note: Oracle Management Server is part of an infrastructure installation. See "The Oracle9iAS Infrastructure" for more information.
Oracle9iAS Reports Services	Oracle9iAS Portal
Oracle9iAS Wireless	Oracle9iAS Portal

Once you configure a component, it cannot be deconfigured, but you can remove its functionality by not starting it when you start the rest of the components in your installation.

The Oracle9iAS Infrastructure

An Oracle9iAS Infrastructure is a type of installation that provides centralized security and management services, configuration information, and data repositories for application server installations.

An infrastructure is installed into its own Oracle home and contains the following pieces:

• Oracle9iAS Single Sign-On: This feature enables users to access multiple accounts and applications with a single username and password, and provides single sign-on service across your entire application server enterprise.

• Oracle Internet Directory: This is an LDAP-compliant directory service that provides centralized storage of information about users, applications, and resources in your enterprise.

• Metadata Repository: This is an Oracle9i Enterprise Edition database that contains schemas and business logic used by application server components and other pieces of the infrastructure.

• Oracle Management Server (optional): This is required if you would like to use Oracle Enterprise Manager Console, a Java-based interface for managing the application server instances, databases, and applications in your enterprise.

  See Also: "About the Oracle Enterprise Manager Console" for more information

When is an Infrastructure Required?

An infrastructure is required for most install types. The one exception is a J2EE and Web Cache installation that is not intended to use Single Sign-On or clustering. Clustering is an operation that involves joining application server installations together to share configuration parameters and application deployment.

See Also: Chapter 14, "Application Server Clustering"

Table 2-3 summarizes the infrastructure requirements for application server install types. The infrastructure must be installed before any middle-tier application server installations that are going to use it.

Table 2-3 Infrastructure Requirements for Application Server Install Types  

Application Server Install Type	Infrastructure Required?
J2EE and Web Cache (not using Oracle9iAS Single Sign-On or clustering)	No
J2EE and Web Cache (using Oracle9iAS Single Sign-On or clustering)	Yes
Portal and Wireless	Yes
Business Intelligence and Forms	Yes
Unified Messaging	Yes

How Infrastructure Pieces Work Together

The pieces of an infrastructure work together as follows:

• Oracle9iAS Single Sign-On stores user information in Oracle Internet Directory.

• Oracle Internet Directory uses the metadata repository as its back-end database.

• Oracle Management Server uses the metadata repository to store information

Figure 2-3 shows the relationship between the pieces of an infrastructure. Note that all pieces of the infrastructure are installed into a single Oracle home.

Figure 2-3 Relationship Between Pieces of an Infrastructure

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How Application Server Installations Use An Infrastructure

Application server installations and their components use an infrastructure in the following ways:

• Components and applications use the Single Sign-on service provided by Oracle9iAS Single Sign-On.

• Application server installations and components store configuration information and user and group privileges in Oracle Internet Directory.

• Components use schemas that reside in the metadata repository.

Configuring an Application Server Installation to Use an Infrastructure

You can configure an application server installation to use an infrastructure at the following times:

• During the installation of any application server install type. The Oracle Universal Installer guides you through this and it is required for all install types except J2EE and Web Cache.

• After the installation of a J2EE and Web Cache install type. You can associate a J2EE and Web Cache install type with an infrastructure at any time if you want to use Single Sign-On or clustering.

Figure 2-1 shows the convention used throughout this book to depict an application server installation using an infrastructure. Note that the application server installation and the infrastructure are each installed into their own Oracle home and may reside on a single host or on separate hosts.

Figure 2-4 Application Server Installation Using an Infrastructure

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Customer Databases

Most Oracle9iAS components use schemas in the metadata repository. However, several components require their schemas to be co-resident with customer data in a specially-tuned database called a customer database. Customer databases are Oracle databases that reside on any system in your enterprise.

Components that Require a Customer Database

The following components require a customer database:

• Oracle9iAS Discoverer

• Oracle9iAS Personalization

• Oracle9iAS Unified Messaging

If you configure any of these components during installation, their setup and configuration will not be complete at the end of installation. You need to take additional steps to install and tune a customer database, load schemas into the database, and finish configuring the component to use the customer database.

If you configure any of these components after installation, you will take the same steps to install and tune a customer database, load schemas into the database, and configure the component to use the customer database.

Components that Can Use a Metadata Repository or Customer Database

The following components can use a metadata repository or a customer database:

• Oracle9iAS Clickstream Intelligence

• Oracle9iAS Portal

If you configure either of these components during installation, they are automatically configured to use the metadata repository and are completely configured and running at the end of installation.

If you configure either of these components after installation, you can use the metadata repository or a customer database. If you use a customer database, you must install and tune the database and load schemas into it as part of the configuration.

Depiction of a Component Using a Customer Database

When you configure an individual component to use a customer database, it does not affect the rest of the components in the installation; they still use the metadata repository. Figure 2-5 shows the convention used throughout this book to depict a component using a customer database. In this figure, all components within the application server installation on Host 1 use the metadata repository on Host 2, except Clickstream, which uses a customer database on Host 3.

Figure 2-5 A Component Using a Customer Database

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Sample Application Server Enterprises

This section shows sample application server enterprises that illustrate the configuration options discussed in this chapter.

Figure 2-6 depicts the simplest application server enterprise: a single J2EE and Web Cache installation with no infrastructure. This installation cannot use Single Sign-On or clustering; however, it is a fully functional J2EE platform with caching capabilities.

Figure 2-6 Single J2EE and Web Cache Installation

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Figure 2-7 depicts two application server installations on one host. In this design, both install types are J2EE and Web Cache that do not use Single Sign-On or clustering, so no infrastructure is required. Note that you can mix different install types on the same host. For example, you can install J2EE and Web Cache and Portal and Wireless on the same host.

Figure 2-7 Two J2EE and Web Cache Installations

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Figure 2-8 shows two J2EE and Web Cache installations on a single host and both use an infrastructure on another host. These application server installations can use Single Sign-On services and clustering because they are associated with an infrastructure. Note that the infrastructure could be on the same host as the J2EE and Web Cache installations, with all three installations using a different Oracle home.

Figure 2-8 Two J2EE and Web Cache Installations with an Infrastructure

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Figure 2-9 shows that two different install types can exist on the same host. Host 1 contains a J2EE and Web Cache installation and a Portal and Wireless installation. It also shows that installations on multiple hosts can use the same infrastructure. The installations on Host1 and Host 3 all use the same infrastructure on Host 2.

Figure 2-9 Installations on Multiple Hosts Using the Same Infrastructure

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Figure 2-10 depicts a single component using a customer database. In this design, all components in the application server installations on Host 1 and Host 3 use the metadata repository on Host 3, except the Clickstream component on Host 2. Clickstream uses the customer database on Host 4.

Figure 2-10 Component Using a Customer Database

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Designing an Application Server Enterprise

This section describes the following steps for designing an application server enterprise:

• Step 1: Choose Your Application Server Install Types

• Step 2: Choose Which Components to Configure

• Step 3: Determine Your Infrastructure Requirements

• Step 4: Choose Your Hosts

• Step 5: Determine Your Customer Database Requirements

• Step 6: Draw Your Application Enterprise Design

Step 1: Choose Your Application Server Install Types

Determine which of the following application server install types you would like to install:

• J2EE and Web Cache

• Portal and Wireless

• Business Intelligence and Forms

• Unified Messaging

Remember, you can start with a single installation and add more installations later.

Step 2: Choose Which Components to Configure

Choose the components you would like to configure. You do not need to configure all components at install time because you can configure components after installation. Also, if you want to use Oracle9iAS Clickstream Intelligence or Oracle9iAS Portal with a customer database, do not configure them during installation; configure them after installation.

Step 3: Determine Your Infrastructure Requirements

If you intend to use any of the following install types, you require an infrastructure:

• J2EE and Web Cache (using Oracle9iAS Single Sign-On or clusters)

• Portal and Wireless

• Business Intelligence and Forms

• Unified Messaging

You must configure Oracle9iAS Single Sign-On, Oracle Internet Directory, and the metadata repository in your infrastructure. If you intend to use Oracle Enterprise Manager Console, Oracle9iAS Forms Services, or Oracle9iAS Interconnect you should also configure Oracle Management Server.

See Also: It is possible to leverage from an existing Oracle Internet Directory in your enterprise. Refer to Oracle Internet Directory Administrator's Guide before proceeding with these steps.

Step 4: Choose Your Hosts

Choose the hosts you will use for application server installations and, optionally, an infrastructure. The following guidelines apply to choosing a host:

• Make sure each host satisfies the operating system and hardware requirements for the installations you intend to put on it. It is recommended that you install an infrastructure on a different host than your application server installations, but you can install an infrastructure and an application server on the same host if the host meets the minimum hardware requirements.

  See Also: Oracle9i Application Server Installation Guide and platform-specific installation guides for more information

• The hosts you use must have a fixed IP address and hostname. They cannot use a dynamic IP address management system such as DHCP.

• Consider whether you want to distribute application server installations over multiple hosts to implement high-availability schemes or clustering.

  See Also: Chapter 13, "High Availability" and Chapter 14, "Application Server Clustering" for more information

Step 5: Determine Your Customer Database Requirements

If you intend to configure any of the following components, you must provide a customer database:

• Oracle9iAS Discoverer

• Oracle9iAS Personalization

• Oracle9iAS Unified Messaging

If you intend to configure the following components, you can configure them to use a metadata repository during installation or you can configure them to use a customer database after installation:

• Oracle9iAS Clickstream Intelligence (it is recommended that you use a customer database for Clickstream if you intend to acquire and store a large amount of data)

• Oracle9iAS Portal

Customer databases can be databases that already exist in your data center, or can be newly installed for use with the application server. In either case, you must make sure that they allow remote access by SYS so components can load data into them. They must be the appropriate version and be properly tuned for the component they support.

See Also: Some components require an Oracle9i database and some will work with an Oracle8i database. See component administration guides for information on customer database requirements.

Step 6: Draw Your Application Enterprise Design

After completing the preceding steps, you should be able to draw an application server enterprise design similar to the ones shown in this chapter. You are now ready to install your application server enterprise.

Installing an Application Server Enterprise

The Oracle Universal Installer guides you through installing and configuring your application server enterprise. This section discusses rules and concepts you should be familiar with before installing an application server, including:

• Oracle Homes

• Coexistence With Other Products

• Port Allocation

• Primary and Secondary Installations

• About Infrastructure Association

  See Also: Oracle9i Application Server Installation Guide for complete installation instructions

Oracle Homes

The following rules apply to Oracle homes used by application server installations and infrastructures:

• You must install each application server installation in its own Oracle home. No other products can be installed in that Oracle home, except Oracle9i Developer Suite (Oracle9iDS).

• You must install an infrastructure in its own Oracle home. No other products (including Oracle9i Developer Suite) can be installed in that Oracle home.

• You can install multiple application server installations and infrastructures on the same host. Each must have its own Oracle home.

• You must use the same operation system user account when installing application server installations and infrastructure on the same host. For example, if you log in as the user "oracle" to perform the first installation on a host, you must log in as "oracle" to perform all subsequent installations on that host.

Coexistence With Other Products

This section describes how application server installations and infrastructures can coexist with other products on the same system:

• You can install application server installations and infrastructures on a host that has other Oracle databases and pre-9.0.2 versions of Oracle application servers. Each product must have its own Oracle home and use different ports. Note that the host must have sufficient hardware to support multiple installations.

• The metadata repository is always configured to use port 1521 and has a service name of the form iasdb.host.domain (for the first infrastructure on a host) and iasdbx.host.domain for any subsequent infrastructures on that host). You should never change these values. If you have another database on the host using the same service name, you must change it before installing the metadata repository.

  If you have another application on the host using port 1521, you must do one of the following before installing the infrastructure:

  • If the other application is an Oracle Net listener using an Oracle9i database, no action is required. The metadata repository will use the existing Oracle Net listener.

  • If the other application is an Oracle Net8 listener using an Oracle8i database, you must change the Net8 listener to use a different port than 1521, or you must upgrade it to the Oracle9i Net listener that runs with the metadata repository.

    See Also: Oracle9i Application Server Installation Guide for instructions on upgrading an existing Net8 listener

  • If the other application is not an Oracle Net or Oracle Net8 listener, reconfigure it to use a different port.

Port Allocation

The application server automatically assigns port numbers for many services during installation. It chooses port numbers from a set of default port numbers and port ranges.

See Also: Appendix D, "Default Port Numbers and Port Ranges"

During installation, the application server assigns unique port numbers in the following ways:

• It internally tracks the port numbers used by all application server installations and infrastructures (running or not running) on a host and will not use the same port number twice.

• It performs a system check to determine if any non-Oracle9iAS processes are running on the port.

Despite this strategy, a port conflict may still occur between the application server and a non-Oracle9iAS process that was not running during the application server installation. Oracle recommends that you review the application server port numbers assigned during installation to determine if there are any port conflicts with the rest of your system.

See Also: "Task 2: Check for Port Conflicts"

Primary and Secondary Installations

If you install multiple application server installations and infrastructures on one host, the first installation is called the primary installation. All succeeding installations on that host are called secondary installations.

Primary installations are unique because they contain the configuration information and password for Enterprise Manager Web site, the Oracle9iAS management tool. When you install a primary installation, you are asked to set the ias_admin password. The ias_admin user is required to use the Enterprise Manager Web site. The ias_admin password is the same for all installations on one host and you must supply it when you install any secondary installations on a host.

See Also: "About the Oracle Enterprise Manager Web Site" for more information

About Infrastructure Association

Once a middle-tier installation is associated with an infrastructure, all subsequent middle-tier installations on the same host will be associated with that infrastructure. This section describes some possible scenarios:

• Scenario 1:
  1. Install an infrastructure on Host A.

  2. Install Portal and Wireless on Host B and associate it with the infrastructure on Host A.

  3. Install J2EE and Web Cache on Host B. If you choose to use an infrastructure, it will automatically use the infrastructure on Host B.

• Scenario 2:
  1. Install an infrastructure on Host A.

  2. Install Portal and Wireless on Host B and associate it with the infrastructure on Host A.

  3. Install Business Intelligence and Forms on Host B. It will automatically use the infrastructure on Host A.

• Scenario 3:
  1. Install an infrastructure on Host A.

  2. Install J2EE and Web Cache on Host A and choose to use an infrastructure. You can choose the infrastructure on Host A or any other infrastructure.

  3. Install Portal and Wireless on Host A. It will automatically use the same infrastructure that the J2EE and Web Cache installation uses.

• Scenario 4:
  1. Install an infrastructure on Host A.

  2. Install a J2EE and Web Cache on Host B. Do not choose to use an infrastructure.

  3. Install Portal and Wireless on Host B and associate it with the infrastructure on Host A. The J2EE and Web Cache installation will continue to not use an infrastructure. Any subsequent middle-tier installations will automatically use the infrastructure on Host A.

Managing an Application Server Enterprise

Once you have installed your application server, you can start managing it. This section introduces the entities that play a primary role in managing the application server. These entities are discussed throughout this book and are as follows:

• Application Server Instances

• Component Instances

• Farms

• Clusters

Application Server Instances

An application server instance is the set of processes required to run the configured components within an application server installation. There can only be one application server instance per application server installation. The terms installation and instance are sometimes used interchangeably; however, it is important to remember that an installation is the set of files installed into an Oracle home and an instance is the set of processes associated with those files.

All application server instances have a name, which you set during installation. You can use this name to identify the instance when using the Oracle9iAS management tools. The hostname is appended to the name you supply to form the instance name. For example, if you assign the name ias1 to an instance on host myserver.mycompany.com, the instance name is ias1.myserver.mycompany.com.

Component Instances

A component instance is the set of processes required to run a component within an application server instance. When you configure a component, either during installation or after installation, one or more component instances are created that you can use to start, stop, and manage the component. This section contains the following two tables that describe component instances:

• Table 2-4, "Component Instances in Application Server Installations"

• Table 2-5, "Component Instances in Infrastructures"

  Table 2-4 Component Instances in Application Server Installations  

  Install Type	Component Instance	Description
  J2EE and Web Cache	BC4J	Business Components for Java. This is a framework for building applications and is deployed to the OC4J_home instance.
  	Clickstream Collector	Clickstream Collector Agent. Although Clickstream is a part of the Business Intelligence and Forms install type, the Clickstream Collector Agent is included with every install type. It collects data from the HTTP Server for Clickstream analysis. You can only use the Clickstream Collector if you are using Clickstream.
  	HTTP Server	Oracle HTTP Server instance.
  	JServ	The Java servlet environment in HTTP Server. This component can only be configured after installation.
  	OC4J_Demos	An OC4J instance that contains OC4J demos.
  	OC4J_home	The default OC4J instance that is created when OC4J is configured. You can use this to deploy applications.
  	Additional OC4J Instances	You can create additional OC4J instances after installation and assign them a name.
  	Web Cache	Oracle9iAS Web Cache instance.
  Portal and Wireless (includes all component instances in J2EE and Web Cache)	OC4J_Portal	An OC4J instance that contains a servlet to support Portal.
  	OC4J_Wireless	An OC4J instance that contains a servlet to support Wireless.
  	Portal	Oracle9iAS Portal instance.
  	Single Sign-On	Oracle9iAS Single Sign-On instance.
  	Wireless	Oracle9iAS Wireless instance.
  Business Intelligence and Forms (includes all component instances in Portal and Wireless)	Clickstream	Oracle9iAS Clickstream Intelligence instance.
  	Discoverer	Oracle9iAS Discoverer instance.
  	Forms	Oracle9iAS Forms Services instance.
  	OC4J_BI_Forms	An OC4J instance that runs servlets that support Discoverer, Clickstream, Forms, Personalization, and Reports.
  	Personalization	Oracle9iAS Personalization instance.
  	Reports	Oracle9iAS Reports Services instance.
  Unified Messaging (includes all component instances in Business Intelligence and Forms)	Unified Messaging	Oracle9iAS Unified Messaging instance.

  Table 2-5 Component Instances in Infrastructures

  Install Type	Component Instance	Description
  Infrastructure	BC4J	Business Components for Java. This instance is not used by the infrastructure.
  	Clickstream Collector	Clickstream Collector Agent. This instance is not used by the infrastructure.
  	HTTP Server	Oracle HTTP Server instance.
  	Internet Directory	Oracle Internet Directory
  	OC4J_DAS	An OC4J instance that provides the Delegated Administration Service for Oracle Internet Directory.
  	OC4J_Demos	An OC4J instance that contains OC4J demos. This instance is not used by the infrastructure.
  	OC4J_home	The default OC4J instance. This instance is not used by the infrastructure.
  	Single Sign-On	Oracle9iAS Single Sign-On

Farms

A farm is a set of one or more application server instances that use the same metadata repository. Exactly one farm is associated with a metadata repository and it has a name of the form host.port.sid, where host is the fully qualified name of the host on which the metadata repository resides, port is the metadata repository listener port, and sid is the metadata repository service id. An example of a farm name is myserver.mycompany.com.1521.iasdb.

The main purpose of a farm is that it designates a set of application server instances that share a repository of configuration and deployment information within the same metadata repository, and are therefore eligible to be clustered together. Clustered instances must share configuration and application information, and membership in a farm enables instances to share information.

Clusters

A cluster is a collection of application server instances with identical configuration parameters and application deployment. Clusters enforce homogeneity between member instances so that a cluster of application server instances appears and functions as a single instance. With appropriate front-end load balancing, any instance in a cluster can serve client requests. Only J2EE and Web Cache install types can be clustered.

See Also: Chapter 14, "Application Server Clustering" for more information

Reconfiguring an Application Server Enterprise

Once your application server is up and running, you may find you need to reconfigure it to provide more functionality or increase its capacity. You can reconfigure your application server in the following ways:

• Configure Components: You can add functionality by configuring components that were not configured at install time.

• Extend application server installations: You can extend an application server installation by installing a higher install type in the same Oracle home. For example, you can extend a Portal and Wireless installation to a Business Intelligence and Forms installation or a Unified Messaging installation.

• Add an infrastructure: You can add your first infrastructure to your application server enterprise in order to enable Single Sign-On or clustering for existing J2EE and Web Cache installations, or you can add a second infrastructure if the load on the metadata repository is too great.

• Associate an instance with an infrastructure (join a farm): You can associate a J2EE and Web installation with an infrastructure, thereby adding it to a farm.

• Change the Database Used By a Component: You can change the database used by an individual component. This is usually done for migration purposes.

  See Also: Chapter 10, "Reconfiguring the Application Server" for details on how to perform the operations described in this section