Installation Considerations

Learn about the information that you must consider before deciding how to install this product.

Installation Differences Between Windows and UNIX Systems

If you are experienced with installing the Oracle components in UNIX environments, note that many manual setup tasks required on UNIX are not required on Windows.

The key differences between UNIX and Windows installations are:

  • Startup and shutdown services

    With Windows, you log in to a user account with Administrator privileges to install the Oracle Database software. You can also specify an Oracle Home User (standard Windows User Account, not an Administrator account) during installation. On Linux and UNIX systems, you must create and use a software owner user account, and this user must belong to the Oracle Inventory group.

  • Environment variables

    With Windows, Oracle Universal Installer sets environment variables such as PATH, ORACLE_BASE, ORACLE_HOME, and ORACLE_SID in the registry. In UNIX systems, you must manually set these environment variables.

    If you have multiple Oracle databases in an Oracle home, then only the SID of the last Oracle database is set in the registry.

  • Operating System Groups

    On Windows systems, Oracle Universal Installer creates ORA_DBA, ORA_OPER, ORA_SID_DBA, ORA_SID_OPER, ORA_HOMENAME_DBA, ORA_HOMENAME_OPER and other groups, which are used for operating system authentication for Oracle Database and Oracle ASM instances. On Linux and UNIX systems, you must create these operating system groups manually, and they are used for granting permission to access various Oracle software resources and for operating system authentication.

  • Account for running Oracle Universal Installer

    With Windows, you log in to a user account with Administrator privileges to install the Oracle Database software. You can also specify an Oracle Home User (standard Windows User Account, not Administrator account) during installation. On Linux and UNIX systems, you must create and use a software owner user account, and this user must belong to the Oracle Inventory group.

See Also:

Oracle Universal Installer and OPatch User's Guide for Windows and UNIX for more information about managing Oracle homes.

Recommended File System

Describes the recommended file system.

Oracle strongly recommends that you install the Oracle database home (Oracle database binaries, trace files, and so on) on Oracle ACFS, NTFS, or ReFS; the database files themselves must be placed on Oracle ASM if using Oracle ACFS; otherwise they can be placed on NTFS, or ReFS. Usage of Oracle ACFS, Oracle ASM, NTFS or ReFS is recommended to ensure security of these files.

Hardware and Software Certification

The platform-specific hardware and software requirements included in this installation guide were current at the time this guide was published.

However, because new platforms and operating system software versions may be certified after this guide is published, review the certification matrix on the My Oracle Support website for the most up-to-date list of certified hardware platforms and operating system versions. This website also provides compatible client and database versions, patches, and workaround information for bugs. The My Oracle Support website is available at

You must register online before using My Oracle Support. After logging in, from the menu options, select the Certifications tab. On the Certifications page, use the Certification Search options to search by Product, Release, and Platform. You can also search using the Certification Quick Links options such as Software eDelivery Cloud, and Lifetime Support.

Third-Party Database Certification for Oracle SQL Developer

You can use Oracle SQL Developer to view metadata and data of several non-Oracle databases.

Oracle Grid Infrastructure for a Standalone Server

Oracle Grid Infrastructure for a standalone server provides the infrastructure to include your single instance database in an enterprise grid architecture.

Oracle Database 12c Release 2 (12.2) combines these infrastructure products into one software installation called the Oracle Grid Infrastructure home. On a single instance database, the Oracle Grid Infrastructure home includes Oracle Restart and Oracle Automatic Storage Management (Oracle ASM) software.

To use Oracle Automatic Storage Management or Oracle Restart, you must first install Oracle Grid Infrastructure for a standalone server before you install and create the database. Otherwise, you must manually register the database with Oracle Restart.

Oracle Cluster Synchronization Services

When you install Oracle Restart, Oracle Universal Installer configures the single-node version of Oracle Cluster Synchronization Services (CSS).

The CSS service is required to enable synchronization between an Oracle ASM instance and the database instances that rely on it for database file storage. Because the service must be running before an Oracle ASM instance or database instance starts, it is configured to start automatically by Oracle Restart before the Oracle ASM instance is started. It must be running if an Oracle database is using Oracle ASM for database file storage.

For single-instance installations, the CSS is installed-in and runs from the Oracle Grid Infrastructure home which is the same home that runs Oracle ASM.

Oracle Universal Installer Overview

Oracle Universal Installer is a Java-based graphical user interface (GUI) tool that enables you to install Oracle software.

Oracle Universal Installer provides the following capabilities:

  • Component and suite installations

  • Globalization support

  • Distributed installation support

  • Unattended silent installations using response files

  • Removal of installed components

  • Multiple Oracle homes support

Oracle Universal Installer can run a silent or a response file installation of Oracle software using response files.

You must use the Oracle Universal Installer 12c to install components into an Oracle Database 12c Oracle home directory.

Oracle Universal Installer automatically installs the Oracle version of the Java Runtime Environment (JRE). This version is required to run Oracle Universal Installer and several Oracle assistants. Do not modify the JRE, unless doing so with a patch provided by My Oracle Support. Visit the following site to find Oracle patches to download:

When Oracle Universal Installer runs, it creates a dbhome_n directory, which keeps track of the components you are installing. Do not modify the contents of this directory. By default, this directory is located at the same directory level as ORACLE_HOME.

Oracle Base Directory

If you install Oracle Database 12c on a computer with no other Oracle software installed, Oracle Universal Installer creates an Oracle base directory for you.

If Oracle software is installed, then one or more Oracle base directories exist. In the latter case, Oracle Universal Installer offers you a choice of Oracle base directories to install Oracle Database.

The Oracle Home User has complete control over the Oracle base for a particular home. For security reasons, different Windows User Accounts used as Oracle Home Users for different Oracle homes are not allowed to share the same Oracle base. However, to support Oracle Database upgrade, Oracle supports the sharing of an Oracle base between a Windows Built-in Account and a Windows User Account. This means that if you choose to reuse an Oracle base from an earlier release of Oracle Database in Oracle Database 12c, then the Oracle Home User of Oracle Database 12c Oracle home has complete control over the Oracle base of the earlier release.

In a default Windows installation, the Oracle base directory appears as follows:


where username is the Oracle Installation User if you choose Windows Built-in Account, else it is the Oracle Home User (standard Windows User Account).


After installing Oracle Database 12c or later with a Windows User Account used as the Oracle Home User, do not install older version of databases and share the same Oracle base directory. During the installation of older releases of Oracle Database, ACLs are reset corresponding to older releases. Thus Oracle Database 12c or later services may not be able to access the Oracle base directory and the files in it.


You can choose to create an Oracle base directory, even if the other Oracle base directories exist on the system.

Oracle Home Directory

Learn about the Oracle Home directory.

Contents of the Oracle Home Environment

The Oracle home directory is located under the Oracle base directory.

For example, in a default Windows installation, if you name the Oracle home directory dbhome_1, it appears in the Oracle base directory as follows:


where username is the installation user if you choose a Windows Built-in Account, else it is the Oracle Home User specified.

An Oracle home corresponds to the environment in which the Oracle components run. This environment includes the following:

  • Location of the installed component files

  • PATH variable pointing to the binary files of the installed components

  • Registry entries

  • Service names

  • Program groups

Oracle homes also have a name associated with them, which is automatically assigned by the installer.

Multiple Oracle Home Components

You can install all Oracle components in multiple Oracle homes on the same computer.

However, some components can only support one active instance at a time. The current (latest) installation renders the previous one inactive. These components are:

  • Oracle Administration Assistant for Windows

  • Oracle Provider for OLE DB

Oracle Inventory Directory

The Oracle Inventory directory is the central inventory location for all Oracle software installed on a server.

By default, the location of the Oracle Inventory directory is C:\Program Files\Oracle\Inventory. This directory is created by default the first time you install Oracle software on a Windows server.

Installing Oracle Database Vault in an Oracle Data Guard Environment

Starting with Oracle Database 12c, Oracle Database Vault is installed by default as part of the Oracle Database installation.

If you plan to use Oracle Data Guard with Oracle Database Vault, then see "Integrating Oracle Database Vault with Oracle Data Guard" in Oracle Database Vault Administrator's Guide.

Oracle Database Vault Default Audit Policy and Initialization Parameters

Oracle Database Vault installs a baseline database auditing policy.

This policy covers the access control configuration information stored in the following:

  • Database Vault database tables

  • Information stored in Oracle Catalog (rollback segments, tablespaces, and so on)

  • Use of system privileges

  • Oracle Label Security configuration

When you install Oracle Database Vault, the security specific database initialization parameters are initialized with the default values.

Consider Memory Allocation and Automatic Memory Management

During a Typical installation, you create your database with Database Configuration Assistant (DBCA), and automatic memory management is enabled. If you choose advanced installation, then you can either specify memory allocation manually, or enable automatic memory management.

With automatic memory management, the Oracle Database instances automatically manage and tune memory for you. With automatic memory management, you choose a memory target, and the instance automatically distributes memory between the system global area (SGA) and the instance program global area (instance PGA). As memory requirements change, the instance dynamically redistributes memory between the SGA and instance PGA.

You can enable automatic memory management either during, or after the database installation. Enabling automatic memory management after installation involves a shutdown and restart of the database.