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Installing Oracle9iAS Discoverer in a multiple machine environment

5.1 Installing Oracle9iAS Discoverer in a multiple machine environment

This chapter explains how to configure Oracle9iAS Discoverer in a multiple machine environment, and contains the following topics:

• Section 5.2, "Why install Oracle9iAS Discoverer on multiple machines?"

• Section 5.3, "About Oracle9iAS installations"

• Section 5.4, "About configuring Discoverer in a multiple machine installation"

• Section 5.5, "About specifying the machine that is going to run the Discoverer Preferences component"

• Section 5.6, "About configuring the tnsnames.ora file in a multiple machine installation"

• Section 5.7, "About using multiple Oracle HTTP Servers and OC4J components?"

5.2 Why install Oracle9iAS Discoverer on multiple machines?

Installing Oracle9iAS Discoverer on multiple machines provides the following benefits:

• scalable capacity and performance

• high availability

• load balancing capability

5.3 About Oracle9iAS installations

Before you can configure Oracle9iAS Discoverer on multiple machines, you need to know about Oracle9iAS Discoverer installations (if you are already familiar with Oracle9iAS installations, skip to Section 5.4, "About configuring Discoverer in a multiple machine installation").

A typical Oracle9iAS Discoverer installation comprises the following:

• one Oracle9iAS Infrastructure Installation, containing the underlying databases, directory server, and management servers necessary for Oracle9iAS middle-tier components

• one or more Business Intelligence and Forms installations on one or more machines

• (optional) one J2EE and Web Cache Installation on one machine, to enable Oracle9iAS Web Cache to act as a proxy

Note: Business Intelligence and Forms and J2EE and Web Cache are both types of Oracle9iAS Installation. For more information, see Oracle9iAS Installation Guide.

In a single machine installation, the Oracle9iAS Infrastructure Installation and the Oracle9iAS Business Intelligence and Forms Installation are located on the same machine but in separate Oracle homes (see figure below).

Figure 5-1 A single machine installation of Oracle9iAS Discoverer

Text description of the illustration infra1.gif

In a multiple machine installation, the Oracle9iAS Infrastructure Installation and a Oracle9iAS Business Intelligence and Forms Installation are typically installed on one machine, and one or more Oracle9iAS Business Intelligence and Forms Installation are installed on other machines (see figure below). These standalone Oracle9iAS components are linked together in an Oracle9iAS farm.

Note: An Oracle9iAS farm is a collection of instances within a single metadata repository.

Figure 5-2 A typical multiple machine installation of Oracle9iAS Discoverer

Text description of the illustration infra2.gif

When you choose the Oracle9iAS Installation type during installation and select the 'Business Intelligence and Forms' option, the Discoverer Services tier is installed on that machine.

You can subsequently install the Business Intelligence and Forms component on other machines and link the standalone machines together in an Oracle9iAS 'farm'.

For example, you might have installed the following:

• one Oracle9iAS Infrastructure Installation on host 1 (e.g. in /home/ias200/installed/902infrastructure)

• one Oracle9iAS Installation (i.e. the Business Intelligence and Forms type) on host 1 (e.g. in /home/ias200/installed/902Discoverer)

• one Oracle9iAS Installation on (i.e. the Business Intelligence and Forms type) on host 2 (e.g. in /home/ias200/installed/902Discoverer)

The figure below shows how this scenario would be represented in Oracle Enterprise Manager.

Text description of the illustration cluster2.gif

You typically use a Oracle9iAS Web Cache proxy on a single URL to distribute the Discoverer Web server requests to other Discoverer machines in the farm (see figure below).

Figure 5-3 Using a Web Cache proxy with an Oracle9iAS farm

Text description of the illustration multi3.gif

Notes:

• You can create Oracle9iAS farms using Oracle Enterprise Manager (for more information, refer to the Oracle Enterprise Manager Help system).

• In a multiple machine installation:
  • the Discoverer Services tier is installed on each machine

  • the Discoverer Preferences component is installed on each machine, but only one Preferences component is used (for more information, see Section 1.7.2.2, "What is the Discoverer Preferences component?" and Section 5.5, "About specifying the machine that is going to run the Discoverer Preferences component")

• You can also spread the Oracle9iAS Discoverer processing load equally across multiple machines (i.e. sometimes referred to as load balancing) using OC4J (see Oracle9i Application Server Concepts and Oracle9iAS Containers for J2EE User's Guide) or Oracle9iAS Web Cache (see Oracle9iAS Web Cache Administration and Deployment Guide).

5.4 About configuring Discoverer in a multiple machine installation

Before you starting configuring Oracle9iAS Discoverer in a multiple machine installation, you will have installed the following:

• an Oracle9iAS Infrastructure component

• one or more Oracle9iAS components (i.e. the Business Intelligence and Forms type) on one or more machines

• one Oracle9iAS components (i.e. the J2EE and Web Cache type) on one machine

To configure Discoverer in a multiple machine installation, do the following:

• if you have not already created a farm, use Oracle Enterprise Manager to create a new farm (for more information, see the Oracle Enterprise Manager Help system)

• use Oracle Enterprise Manager to add the Oracle9iAS Discoverer components to the farm (for more information, see the Oracle Enterprise Manager Help system)

• configure Oracle9iAS Web Cache to act as a proxy (for more information, see Oracle9iAS Web Cache Administration and Deployment Guide)

• specify the machine that is going to run the Discoverer Preferences component (for more information, see Section 5.5, "About specifying the machine that is going to run the Discoverer Preferences component")

• make sure that each machine contains the same database names and aliases information (for more information, see Section 5.6, "About configuring the tnsnames.ora file in a multiple machine installation")

5.5 About specifying the machine that is going to run the Discoverer Preferences component

In a multiple machine installation, only one machine runs the Discoverer Preferences component. This machine is referred to as the Preference Server machine. You must configure the other machines in a multiple machine installation to use the Preferences component running on the Preference Server machine, instead of running their own Preferences component. The diagram below shows how additional Discoverer machines reference the preferences on the Preference Server machine, which are stored in the file pref.txt (for more information about the location of configuration files, see Section A.2, "List of Discoverer file locations").

Text description of the illustration mm1.gif

To specify that other machines in a multiple machine installation use the Preferences component running on the Discoverer Preference Server machine, you:

• find out the name of the Discoverer Preference Server machine (for more information, see Section 5.5.1, "How to find out the name of the Discoverer Preference Server machine")

• modify the register session scripts of other machines in the multiple machine installation to use the Discoverer Preference Server machine (for more information, see Section 5.5.2, "How to modify the register session scripts of other machines in the multiple machine installation to use the Preference Server machine")

5.5.1 How to find out the name of the Discoverer Preference Server machine

To find out the name of the machine that you want to run the Preferences component (i.e. the Discoverer Preference Server machine):

1. On the machine that you want to designate as the Discoverer Preference Server machine, open the following register session file in a text editor:
   • on UNIX, open the registersession.sh file

   • on Windows, open the registersession.bat file

   To find out the location of the file, see Section A.2, "List of Discoverer file locations".

2. Locate the '-preference' command in the register session script:

   ... -a -preference -a <current_machine_name>OracleDiscovererPreference9.0.2 ...
   

   where <current_machine_name> is the name of the current machine.

3. Make a note of the <current_machine_name> value (i.e. the name of the current machine).

   The <current_machine_name> is the name that you use to designate the current machine as the Discoverer Preference Server machine. You use this name in register session scripts of other machines in the multiple machine installation.

4. Close the text editor.

5.5.2 How to modify the register session scripts of other machines in the multiple machine installation to use the Preference Server machine

Having identified the name of the machine that is going to run the Preferences component (i.e. the Preference Server machine), you must now make sure that other machines do not run their own Preferences component.

To make sure other machines in the multiple machine installation use the Discoverer Preference Server machine, on every other machine in the installation do the following:

1. Stop the Preferences component (for more information, see Section 6.7, "How to start and stop the Preferences component").

2. Unregister the Session component (for more information, see Section 6.6, "How to register and unregister the Discoverer Session component with the OAD").

3. Open the following register session file in a text editor:
   • on UNIX, open the registersession.sh file

   • on Windows, open the registersession.bat file

   To find out the location of the file, see Section A.2, "List of Discoverer file locations".

4. Locate the '-preference' command in the register session script:

   ... -a -preference -a <current_machine_name>OracleDiscovererPreference9.0.2
   

   where <current_machine_name> is the name of the current machine.

5. Remove the <current_machine_name> value and prefix OracleDiscovererPreference9.0.2 with the name of the Discoverer Preference Server machine.

   For example, if the Preference Server machine is called mc_1234, you would change the register session script to:

   ... -a -preference -a mc_1234OracleDiscovererPreference9.0.2 ...
   

6. Register the Session component (for more information about registering the Session component, see Section 6.6, "How to register and unregister the Discoverer Session component with the OAD").

5.6 About configuring the tnsnames.ora file in a multiple machine installation

The tnsnames.ora file contains the names and aliases of all the databases that users can access using Oracle9iAS Discoverer.

Each server machine in a multiple machine Discoverer installation must have the same tnsnames.ora file.

Text description of the illustration mm2.gif

If you install additional Discoverer Server machines, you must make sure that the tnsnames.ora files on the different machines are the same by doing one of the following:

• copy the tnsnames.ora file from an existing Discoverer Server machine to the same location on each additional Discoverer Server machine that you want to deploy, replacing the existing file (to find out the location of this file, see Section A.2, "List of Discoverer file locations")

• edit the tnsnames.ora file on each additional Discoverer Server so that it contains the same database names and aliases as an existing Discoverer Server machine, as follows:
  1. Using a text editor, open the tnsnames.ora file on each additional Discoverer Server machine that you want to deploy (for more information about the location of configuration files, see Section A.2, "List of Discoverer file locations").

  2. Edit the database names and aliases so that they match the database names and aliases in the tnsnames.ora file on an existing Discoverer Server machine.

  3. Save the tnsnames.ora file.

All Discoverer Servers now have access to the same database names and aliases.

Hint: Several versions of the tnsnames.ora file might exist on a machine. Make sure that you use the tnsnames.ora file listed in Section A.2, "List of Discoverer file locations".

5.7 About using multiple Oracle HTTP Servers and OC4J components?

In addition to using multiple machine installations, you can enhance Oracle9iAS Discoverer performance by increasing the number of Oracle HTTP Servers and Oracle9iAS Container for J2EE (OC4J) components. Two typical configurations are:

• a single installation of the Oracle HTTP Server (and MOD_OC4J), and multiple installations of Oracle9iAS Container for J2EE (for more information, see Section 5.7.1, "Using Oracle9iAS Discoverer with a single installation of the Oracle HTTP Server and multiple installations of Oracle9iAS Containers for J2EE")

  
  
  Text description of the illustration mm3.gif

  This type of configuration provides increased performance and high availability of the Oracle HTTP Server

• multiple installations of Oracle HTTP Server (and MOD_OC4J), and multiple installations of Oracle9iAS Container for J2EE (for more information, see Section 5.7.2, "Using Oracle9iAS Discoverer with multiple installations of Oracle HTTP Server, and multiple installations of Oracle9iAS Containers for J2EE")

  
  
  Text description of the illustration mm4.gif

  This type of configuration provides increased performance and high availability of both the Oracle HTTP Servers and the Discoverer Servers.

5.7.1 Using Oracle9iAS Discoverer with a single installation of the Oracle HTTP Server and multiple installations of Oracle9iAS Containers for J2EE

In this scenario, you:

• install the Oracle HTTP Server component on a single machine (for more information, see Oracle9i Application Server Installation Guide).

• install Oracle9iAS Container for J2EE components on multiple machines (for more information, see Oracle9i Application Server Concepts and Oracle9iAS Containers for J2EE User's Guide)

• configure MOD_OC4J so that it is aware of the existence of all of the Oracle9iAS Container for J2EE machines (for more information, see Oracle9i Application Server Concepts and Oracle9iAS Containers for J2EE User's Guide)

5.7.2 Using Oracle9iAS Discoverer with multiple installations of Oracle HTTP Server, and multiple installations of Oracle9iAS Containers for J2EE

In this scenario, you:

• install Oracle HTTP Server components on multiple machines (for more information, see Oracle9i Application Server Installation Guide)

• install Oracle9iAS Container for J2EE components on multiple machines (for more information, see Oracle9i Application Server Concepts and Oracle9iAS Containers for J2EE User's Guide)

• configure each instance of MOD_OC4J so that each instance is aware of the existence of all of the Oracle9iAS Container for J2EE machines (for more information, see Oracle9i Application Server Concepts and Oracle9iAS Containers for J2EE User's Guide)