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Tuning WebLogic JRockit with WebLogic Server on Linux

# Introduction

Welcome to Tuning WebLogic JRockit with WebLogic Server on Linux. This document is specifically designed for WebLogic JRockit users who are running the JVM with BEA WebLogic Server 8.1 on the Linux operating system. Much of the information in this guide is similar to that in Tuning WebLogic JRockit 8.1 JVM, however this document contains information and examples specific to Linux users.

This Introduction further describes the contents of this guide and answers some basic questions about tuning WebLogic JRockit. It includes information on the following subjects:

- Why is Tuning Necessary?
- How Do You Tune a JVM?
- Migrating Applications to WebLogic JRockit
- What Linux Operating Systems Does WebLogic JRockit Support?
- Installing WebLogic JRockit with WLS on Linux

# Why is Tuning Necessary?

Although WebLogic JRockit JVM automatically adapts to its underlying hardware and to the application running on it, the JVM cannot know everything about your system. For example, how much memory do you want the JVM to use? Or, how long should the maximum pauses be, to work best within the tolerances of your application? To instruct WebLogic JRockit on how to handle this critical processing functions, you can configure—or tune—many aspects of your JVM's performance by setting appropriate configuration options at startup.

# How Do You Tune a JVM?

While WebLogic JRockit uses many of the standard start-up options available for other JVMs—such as logging options like `-version`, which tells WebLogic JRockit to display its product version number and `-verbose`, which tells JRockit to display verbose output—actual tuning of the JVM requires manipulating WebLogic JRockit's two main subsystems: the memory management system (often called garbage collection), and the thread system.

Tuning these subsystems requires setting non-standard, or `-X`, options at startup. This guide documents the different startup options and tells you what you need to know about these subsystems to be able to tune them successfully. By using these options and following the recommendations suggested in this guide, you can ensure that you application performs optimally. You should note that, on Linux, these options do not differ from those used with other O/Ss, such as Windows.

# Migrating Applications to WebLogic JRockit

WebLogic JRockit is the default JVM shipped with BEA WebLogic Server. Although there are other JVMs available on the market today that you can use to develop Java applications, BEA Systems recommends that you use WebLogic JRockit JVM as the production JVM for any application deployed on WebLogic Server. Migrating to WebLogic JRockit with WebLogic Server on Linux describes basic environment changes necessary to migrate to WebLogic JRockit JVM from Sun Microsystems HotSpot JVM or any other third-party JVM.

# What Linux Operating Systems Does WebLogic JRockit Support?

This version on WebLogic JRockit SDK supports these versions of the Linux operating system:

- For 32-bit processors (Intel Pentium II—or comparable—and higher):

- Red Hat Enterprise Linux AS / ES / WS 2.1
- SuSE SLES 8.0 (United Linux 1.0)

- For 64-bit processors (Intel Itanium 2 or higher):

- Red Hat Linux Advanced Server for Itanium Processor 2.1
- Red Hat Linux Advanced Workstation for Itanium Processor 2.1

For complete platform support details, please refer to:

http://edocs.bea.com/wljrockit/docs81/certif.html

# Installing WebLogic JRockit with WLS on Linux

Installing WebLogic JRockit to run with WebLogic Server on a Linux machine is handled no differently that installing it in any other configuration. You can either install the JVM as part of the BEA WebLogic Platform product suite (which includes WLS) or you can install it as a standalone application. With either of these installation methods, you also have the option of installing it in either a graphic mode or from the console (command line mode), should you not be using a GUI.

To install WebLogic JRockit as part of WebLogic Platform, please refer to Installing WebLogic Platform, specifically:

- Installing WebLogic Platform Using Graphical-Mode Installation
- Installing WebLogic Platform Using Console-Mode Installation

To install WebLogic JRockit as a standalone application, please refer to Installing WebLogic JRockit 8.1 SDK, specifically:

- Installing WebLogic JRockit SDK
- Installing and Uninstalling WebLogic JRockit SDK in the Console Mode