3 Before You Begin Installation

This chapter provides recommendations for a successful Enterprise Deployment installation.

3.1 Best Practices for Installing and Configuring Enterprise Deployments

Adherence to the following practices may save you time as you install and configure the architectures described in this guide:

Before each configuration step, make a complete file system backup of the entire Oracle home, capturing the previous step on all computers at the same time. If there is a problem at any point during installation or configuration, you can then return to the previous state by restoring the backup to all computers at the same time.

Note:

On UNIX systems, when using the tar utility, issue the tar or untar command as the root user. Some of the executables in Oracle software are owned by root. Backing up files in this way as the root user does not change ownership of the file system, or symbolic links inside folders and subfolders.

Try to keep user IDs, group IDs, Oracle home paths and directory structures the same on both computers for each component installed.
Use the static ports feature of the installer when installing components, to ensure that the same ports are used on both computers for each component. (Ideally, you would use the same staticports.ini file for the first and second installations of a given installation type on each tier.)

3.2 Hardware Sizing Guidelines

All Enterprise Deployment configurations in this guide use two servers for each tier to provide failover capability; however, this does not presume adequate computing resources for any application or user population. If the system workload increases such that performance is degraded, you can add servers to the configuration by repeating the instructions for the installation and configuration of the second server on the tier (WEBHOST2, APPHOST2, INFRADBHOST2) to add a third server where it is needed.

To determine hardware needs with a greater degree of precision, you might consider the options presented in Table 3-1.

Table 3-1 Hardware Sizing Options

Option	Benefit	Disadvantage
Create a prototype of the deployment architecture and stress test it	Accurate estimate; provides ability to extrapolate Accomodates custom scenarios and complex implementations Incorporates third-party components (firewalls, load balancing router); exposes performance and network-specific issues	Time and effort required to configure Additional software for load simulation required
Use the iSizer tool	Fast and easy to use Works best in common implementations with one component for each server	Inexact results for systems with third-party components, many custom implementation details Results difficult to extrapolate in multiple-component architectures

3.3 Managing Oracle Application Server Component Connections

In order to ensure consistent availability of all services, you should ensure that the connection time out values for all Oracle Application Server components are set to a lower time out value than that on the firewall and Load Balancing Router. If the firewall or Load Balancing Router drops a connection without sending a TCP close notification message, then Oracle Application Server components will continue to try to use the connection when it is no longer available.

This guide provides the following instructions for configuring time out values in Oracle Application Server: