About This Manual

This manual is useful for system managers who want to get the maximum benefit from their Digital UNIX® system. Improving the performance of a system can entail tuning one or more of the following areas: applications you are running, the virtual memory subsystem, the disk I/O subsystem, file system layout policies, or the network subsystem.

It is often difficult to determine the cause of a problem or bottleneck that is affecting performance. This manual will assist you in determining where the problem resides, what the underlying cause may be, and how to resolve it. Because the Digital UNIX operating system can be used in many different types of environments, the resolutions are more suggestions than they are hard answers.

Recommended Interface

For Digital UNIX Version 4.0 and higher, Digital recommends that you use the graphical interface to system administration. The graphical interface is presented by the SysMan, an application that is loaded by default when the Common Desktop Environment (CDE) software is loaded on your system. If your system is a workstation or a server with the CDE software, select the System Management Utilities from the Applications window to determine how the utilities can help you perform system administration tasks.

Audience

This manual is intended for system administrators who are responsible for managing a Digital UNIX operating system. Administrators should have in-depth knowledge of operating system concepts, commands, and utilities. It is also especially important for administrators to understand how their systems are being used. Such understanding can be crucial to the success of an effort to tune a system for better performance.

New and Changed Features

The following additions and changes have been made to this manual for the Version 4.0 release of Digital UNIX:

• Chapter 2 - Added summary information on two new monitoring tools: Performance Manager and Atom. Also added additional information on LSM monitoring commands.

• Chapter 4 - Moved the contents of this chapter, Optimizing Applications, to the Programmer's Guide.

• Appendix B - Added description of many sysconfigtab attributes that were added for the Digital UNIX V4.0 release. Information on the minimum and maximum values for the various attributes was dropped from this appendix because the sysconfig -Q command now provides this information.

Organization

This manual consists of three chapters and two appendixes:

Chapter 1	Provides an overview of the system components that can be adjusted to improve performance.
Chapter 2	Describes the tools used to analyze how system resources are being used.
Chapter 3	Provides information about how to tune your system for better performance.
Appendix A	Describes special tuning considerations related to low-memory (24-MB) Alpha systems.
Appendix B	Describes system-resource configuration attributes.

Related Documents

The System Administration manual provides information on managing and monitoring your system.

The Programmer's Guide provides information on the tools for programming on the Digital UNIX operating system. It also provides information on how to optimize the code used to create an application program and how to optimize the results of the build process.

The printed version of the Digital UNIX documentation set is color coded to help specific audiences quickly find the books that meet their needs. (You can order the printed documentation from Digital.) This color coding is reinforced with the use of an icon on the spines of books. The following list describes this convention:

Audience	Icon	Color Code
General users	G	Blue
System and network administrators	S	Red
Programmers	P	Purple
Device driver writers	D	Orange
Reference page users	R	Green

Some books in the documentation set help meet the needs of several audiences. For example, the information in some system books is also used by programmers. Keep this in mind when searching for information on specific topics.

The Documentation Overview, Glossary, and Master Index provides information on all of the books in the Digital UNIX documentation set.

Reader's Comments

Digital welcomes any comments and suggestions you have on this and other Digital UNIX manuals.

You can send your comments in the following ways:

• Fax: 603-881-0120 Attn: UEG Publications, ZK03-3/Y32

• Internet electronic mail: readers_comment@zk3.dec.com

  A Reader's Comment form is located on your system in the following location:

  /usr/doc/readers_comment.txt
  

• Mail:

  Digital Equipment Corporation
  UEG Publications Manager
  ZK03-3/Y32
  110 Spit Brook Road
  Nashua, NH 03062-9987

  A Reader's Comment form is located in the back of each printed manual. The form is postage paid if you mail it in the United States.

Please include the following information along with your comments:

• The full title of the book and the order number. (The order number is printed on the title page of this book and on its back cover.)

• The section numbers and page numbers of the information on which you are commenting.

• The version of Digital UNIX that you are using.

• If known, the type of processor that is running the Digital UNIX software.

The Digital UNIX Publications group cannot respond to system problems or technical support inquiries. Please address technical questions to your local system vendor or to the appropriate Digital technical support office. Information provided with the software media explains how to send problem reports to Digital.

Conventions

The following conventions are used in this manual:

% $	A percent sign represents the C shell system prompt. A dollar sign represents the system prompt for the Bourne and Korn shells.
#	A number sign represents the superuser prompt.
% cat	Boldface type in interactive examples indicates typed user input.
file	Italic (slanted) type indicates variable values, placeholders, and function argument names.
[ | ] { | }	In syntax definitions, brackets indicate items that are optional and braces indicate items that are required. Vertical bars separating items inside brackets or braces indicate that you choose one item from among those listed.
. . .	A vertical ellipsis indicates that a portion of an example that would normally be present is not shown.
cat(1)	A cross-reference to a reference page includes the appropriate section number in parentheses. For example, cat(1) indicates that you can find information on the cat command in Section 1 of the reference pages.
Ctrl/x	This symbol indicates that you hold down the first named key while pressing the key or mouse button that follows the slash. In examples, this key combination is enclosed in a box (for example, [Ctrl/C]).