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Using Multiple Oracle Homes

Introduction

The Oracle Universal Installer supports the installation of several active Oracle homes on the same machine. An Oracle home is the system context in which Oracle products run. This context consists of the directory location where the products are installed, the corresponding system path setup, and where applicable, the program groups associated with the products installed in that home, and the services running from that home.

Multiple Oracle Homes

The Oracle Universal Installer supports the installation of several active Oracle homes on the same machine as long as the products support this at runtime. You can have multiple versions of the same product or different products running from different Oracle homes concurrently. Products installed in one home will not conflict or interact with products installed in another home. You can update software in any home at any time, assuming all Oracle applications/services/processes installed on the target home are shut down. Processes from other homes may still be running.

Target Home

The Oracle home currently accessed by the Oracle Universal Installer for installation or deinstallation is the target home. In order to upgrade or remove products from the target homes, those products must be shut down/stopped.

Product Types

Different levels of support are available with multiple Oracle homes for the following product types:

• Products that can be installed once in any new Oracle home. Ensure that the previous product installation is first removed so that only one copy/version of that application can run at the same time. If such product is already installed, and you try to install it again on a different home, the Oracle Universal Installer issues an error message.

• Products that can be installed multiple times, in different homes, on the same machine, with no conflicts or interaction at install-time, run-time, or deinstall-time. These are products which can be used concurrently.

Note: The installation guide of your products will specify what type they are and whether they can be installed once in a home or multiple times.

Home Selector (Available on Win32 Platforms)

Overview

The Home Selector is part of the installation software and is installed with the Oracle Universal Installer. It is installed in <oui_location>\HomeSelector.

If your application is not installed in one of the Oracle homes, you need to ensure it uses the right product version, by pointing it to the right home. That specific (target) home must take precedence over the other homes in your path when you launch your application.

The Home Selector enables you to easily change your primary Oracle home (the one that appears first in the PATH environment variable). If you need to switch the active home or need to perform batch work which requires a "default home" to be active, the Oracle Home Selector can be used to change the Windows NT system settings.

When using the Home Selector to make a specific $ORACLE_HOME the active one, the software installation in question is moved to the top of the PATH variable, making it the first directory to be scanned for executables and library files.

How It Works

When you perform an install on a system, the first $ORACLE_HOME will be named the "DEFAULT_HOME" and will register itself in the Windows NT registry under the key:

  HKEY_LOCAL_MACHINE
    Software
      Oracle

This is the default Windows NT registry hive which contains all the "generic" Oracle settings. Also the PATH variable is adjusted and the BIN directory of the $ORACLE_HOME is added to the environment variable.

Starting with Oracle 8.0.4, the first version to be multiple $ORACLE_HOME aware, some additional parameters will also be written to the key:

  HKEY_LOCAL_MACHINE
    Software
      Oracle
        Home0

With the Oracle Universal Installer, you can change the "DEFAULT_HOME" name to something else. Also, it registers all Oracle settings in the "Home0" subkey of the ORACLE key.

When an additional $ORACLE_HOME is added to the system, the PATH variable is adjusted again to add the new BIN directory of the newly installed Oracle software. The registry variables are written to a key named "HOMEx," where X is the next available number in the Oracle key.

When several $ORACLE_HOMEs are installed, the executables referenced are all found in the first $ORACLE_HOME\BIN directory of the PATH variable. When you want to switch the order of the PATH variable, you can use the Home Selector to switch the order of the $ORACLE_HOMEs installed on the system.

Together with the installation and registration of the software in the registry, a second series of registry variables are written in the following key:

  HKEY_LOCAL_MACHINE
    Software
      Oracle
        ALL_HOMES

This is the starting point for the list of all $ORACLE_HOME installations, done on this system.

The following variables are written in this key:

• HOME_COUNTER: Number of Oracle home directories already present on the system. This counter is a number, exactly 1 higher as the last ID subkey present.

• LAST_HOME: ID number of the currently active $ORACLE_HOME

• IDx: List of registry key's containing the name, number and installation directory of this ORACLE_HOME. The first installation is written in ID0, the next one in ID1, etc.

If the Home Selector is started in interactive mode, the registry hive "ALL_HOMES" is read, including all subkeys, and a dialog box will be dispayed with all available installations. As soon as the you select one, the PATH variable will be adjusted at the system level.

In order to make batch processing possible, this tool also has a commandline interface, making it possible to use the tool to switch the PATH settings while executing a series of commands:

ohsel -switch "Oracle Home Name"

The name of this $ORACLE_HOME is one of the names found in the ID subkeys.

Oracle Home Directory Structure for Windows Platform

A typical Oracle home on Windows platforms contains the files and directories shown in Table 2-1.

Table 2-1 Oracle Home Directory for Windows Platforms

Oracle Home Directory	Contents
\BIN	Product executables and DLLs
\DBS	Common message files
\PROD1	PROD1 product files
\PROD2	PROD2 product files

Optimal Flexible Architecture Directory Structure (on Solaris)

The Optimal Flexible Architecture (OFA) standard is a set of configuration guidelines for fast, reliable Oracle databases that require little maintenance.

OFA is designed to:

• organize large amounts of complicated software and data on disk to avoid device bottlenecks and poor performance

• facilitate routine administrative tasks such as software and data backup functions, which are often vulnerable to data corruption

• alleviate switching among multiple Oracle databases

• adequately manage and administer database growth

• help eliminate fragmentation of free space in the data dictionary, isolate other fragmentation, and minimize resource contention

The OFA directory structure is described below.

ORACLE_BASE Directory

ORACLE_BASE specifies the BASE of the Oracle directory structure for OFA-compliant databases. A typical ORACLE_BASE directory structure is described in Table 2-2. When installing an OFA-compliant database using the Oracle Installer, ORACLE_BASE is by default set to /pm/app/oracle.

Table 2-2 Sample ORACLE_BASE Directory Structure and Content

admin	administrative files
doc	online documentation
local	subtree for local Oracle software
product	Oracle software

ORACLE_HOME Directory

The following is an example of an Oracle Server Install.

If you install an OFA-compliant Oracle Server, the ORACLE_HOME directory is /mount_point/app/oracle/product/release_number. ORACLE_HOME directory structure and content are described in Table 2-3. Under UNIX, the ORACLE_HOME directory might contain the following subdirectories, as well as a subdirectory for each Oracle product selected.

Note: The examples in this table are for sample only. The directories that appear in your own Oracle Home will depend upon whether the corresponding products are installed and the version of the Oracle database you are running.

Table 2-3 Sample ORACLE_HOME Directory Structure and Content

assistants	configuration Assistants
bin	binaries for all products
ctx	interMedia Text cartridge
dbs	initsid.ora, lksid
install	install related files
lib	Oracle product libraries
jlib	Java classes
md	Spatial cartridge
mlx	Xerox Stemmer (for interMedia Text cartridge)
network	Net8
nlsrtl	NLS runtime loadable data
ocommon	common files for all products
odg	data gatherer
opsm	Parallel Server Manager Components
oracore	core libraries
ord	data cartridges
otrace	Oracle TRACE
plsql	PL/SQL
precomp	precompilers
rdbms	server files and libraries required for the database
slax	SLAX parser
sqlplus	SQL*Plus

Creating an Oracle Home

To create an Oracle home, follow the steps below.

1. Run the Oracle Universal Installer.

2. In the File Locations page, enter the Oracle home settings for the installation session under Destination. See Table 2-4 for a description of the fields in this section of the screen.

Note: The Name field only appears in Windows platforms.

3. Continue with your installation. Refer to Chapter 1, "Using the Oracle Universal Installer" for detailed information.

Table 2-4 Oracle Installation Settings in Destination

Settings	Functions
Name	For Windows platforms, Oracle homes are identified by name, and the Oracle home name identifies the program group associated with a particular Oracle home, and the Oracle services installed on the associated home. The Oracle home name must be 1 to 16 characters long and can only include alphanumeric characters and underscores.
Path	Enter an Oracle home and its full path or select an Oracle home from a drop down list of existing Oracle Homes. The Oracle home location is the directory where products are installed. List of Oracle homes on Windows platforms: all Oracle homes that are already created using the Oracle Universal Installer all homes created using the previous Oracle Installer (ORCA-based) the home that the ORACLE_HOME environment variable points to List of Oracle homes on UNIX: all Oracle homes that are already created using the Oracle Universal Installer all homes as defined in the /var/opt/oratab file the home that the ORACLE_HOME environment variable points to If none of these homes exists, a default home is calculated based on the disk volume with the largest amount of free space. Datafiles may or may not be installed within an Oracle home. You may use the Browse button to choose a directory to install your product. For Windows platforms: it must be a valid path that is not in the Windows directory. Different homes cannot share the same location.

ORAPARAM.INI File

Note: A typical user does not need to modify the ORAPARAM.INI file. This file is manipulated when you are building your own installation using the Oracle Universal Installer.

The ORAPARAM.INI is the Oracle Universal Installer's initialization file. Edit the parameters according to sample file provided. The file provides parameters for the following:

[Oracle]

DISTRIBUTION

Set DISTRIBUTION to TRUE if the ORAPARAM.INI file is on a distribution media. A distribution media can be a CD-ROM or the Web.

SOURCE

Location of your staging area (the products.jar file). This location is relative to the directory where oraparam.ini exists.

LICENSE_LOCATION

Location of a text file for License information. This location is relative to the directory where oraparam.ini exists. The legal terms file should be a plain text file.

If you specify the LICENSE_LOCATION variable, the Oracle Universal Installer will ask for license acceptance after you click the Next button on the "Welcome" screen. The Oracle Universal Installer will let the user proceed only after license is accepted.

This parameter is ignored if the file is not found.

LICENSE_TITLE

The value of this variable displays as the title of the license agreement. The Oracle Universal Installer only reads this value if the license dialog is displayed. That is, if the LICENSE_LOCATION variable has a valid value.

JRE_LOCATION

Location to the Java Runtime Environment (JRE) which will be used by the Oracle Universal Installer.

Note: For a single install to point to two different JRE versions, move the oraparam.ini file one level below its original location and then specify the individual platform's JRE location. For example, if the original location is in the Disk1/install directory, move it to the Disk1/install/win32 or the Disk1/install/solaris directory and then specify the individual platform's JRE location.

OUI_LOCATION

Location to the Oracle Universal Installer files.

JRE_MEMORY_OPTIONS

Set these to increase the initial heap size for JRE.

DEFAULT_HOME_LOCATION

Location of the default home.

DEFAULT_HOME_NAME

The default name for the Oracle Home. This parameter is used only if the install takes place on a machine with no previous Oracle installations. This parameter is used only on Windows platforms.

NO_BROWSE

List directories which you do not want to browse. These are typically large directories which will take a long time to list. For example, /net, /nfs.

NLS_ENABLED

Set NLS_ENABLED to TRUE for the Oracle Universal Installer to enable NLS support. Set NLS_ENABLED to FALSE to disable the installation session translations. The Oracle Universal Installer displays in English even if you run on a non-English system.

BOOTSTRAP

In the case of installing products that span multiple CDs, a "bootstrap" occurs in which temporary copies of OUI and JRE are placed in the TEMP or TMP directory so that these applications can be launched when you change CD-ROMs.

As a user/developer of an install, you need to set BOOTSTRAP to True or False. BOOTSTRAP tells the Oracle Universal Installer to attempt a bootstrap. Set BOOTSTRAP to True before cutting CDs, but set it to False once you have copied the staging area to the hard disk.

If you are running a multiple CD install, you must set the bootstrap variable BOOTSTRAP=TRUE.

Otherwise, the first CD cannot be ejected on Solaris because the file system is busy. The Oracle Universal Installer is holding open several files on the CD including the JRE executable, and on Solaris, ejectable volumes cannot be ejected if a process has opened files on the volume.

Setting the BOOTSTRAP variable to TRUE informs the Oracle Universal Installer to copy the Oracle Universal Installer classes and the JRE executables to a temporary directory where you can launch them; thereby freeing the CD device.

You may also need to launch runInstaller in the background by using the ampersand character:

./runInstaller &

By launching runInstaller in the background, you can change your current directory after you launch the Oracle Universal Installer so that you can eject the CD.

You may want to create a shell script that launches the Oracle Universal Installer in the background and then exits. If you choose to create a shell script, remember to also pass all parameters that passed to the shell script along to runInstaller in case you want to pass a response file name to run a silent installation.

OUI_VERSION = <2.0.1.0.0>

Set the version of the Oracle Universal Installer you are using.

Note: You must set the Universal Installer version correctly in order for the bootstrap to work.

[IMAGES]

To show advertisements during an install, you must specify each image as a separate variable. For example:

FILE1=../stage/adimages/adimage0.gif

FILE2=../stage/adimages/adimage1.gif

This means the variables have to have the same structure of:

FILE<image_number>=<image location relative to oraparam.ini file's location>

Images display in the order they are listed in the oraparam.ini file. The images will be shown on equal intervals throughout the install session. All images must be in .gif format. Oracle Universal Installer displays the images as follows:

The amount of space allocated to advertisement images is subject to change in future Oracle Universal Installer releases.

Note: Images are only visible to users running Oracle Universal Installer version 1.5.1.4.x or higher. Advertisement images should not exceed 160 (width) x 225 (height) pixels.

A sample ORAPARAM.INI file is shown below.

  
[Oracle] 
DISTRIBUTION=TRUE 
#Set DISTRIBUTION to TRUE if the ORAPARAM.INI file is on a distribution media. A 
distribution media can be a CD-ROM or the Web. 

SOURCE=../stage/products.jar 
#Location of the products.jar file. This location is relative to the directory 
where oraparam.ini exists.

LICENSE_LOCATION= 
#Location of a text file for License information. This location is relative 
to the directory where oraparam.ini exists. 
#After you click the Next button on the Welcome page, the Oracle Universal 
Installer will ask for license acceptance. If this file exists, the Oracle 
Universal Installer will let the user proceed only after license is accepted. 

JRE_LOCATION=../stage/Components/oracle/swd/jre/1.1.6.2.1o/2/DataFiles/Expanded
/ojre 
#Relative location to the Java Runtime Environment (JRE) which will be used by 
the Oracle Universal Installer 

OUI_LOCATION=../stage/Components/oracle/swd/oui/1.5.1.4.2/1/DataFiles/Expanded 
#Relative location to the Oracle Universal Installer files 

DEFAULT_HOME_NAME="OUIHome" 
#The default name for the Oracle Home. This parameter is used only if the 
install takes place on a machine with no previous Oracle installations. This 
parameter is used only on Windows platforms. 

HLP_LOCATION= 
#For future use only

EWT_LOCATION= 
#For future use only 

NLS_ENABLED=TRUE 
#Set NLS_ENABLED to FALSE to disable the translations. The Oracle Universal 
Installer displays in English even if you run on a non-English system. 

JRE_MEMORY_OPTIONS=-ms16m -mx32m 
#Set these to increase the initial heap size for JRE.  

NO_BROWSE= 
#list directories which you do not want to browse. These are typically 
large directories which will take a long time to list. 
# =/net, /nfs 

OUI_VERSION = <1.7.0.1.0>
Set the version of the Oracle Universal Installer you are using. Note: you must 
set the version correctly in order for the bootstrap to work.

[IMAGES]
FILE1=images/installAd0.gif
FILE2=images/installAd1.gif

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