About This Guide
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## About This Guide

IRIX Admin: Disks and Filesystems is one guide in the IRIX Admin series of IRIX system administration guides. It discusses important concepts and administration procedures for disks, filesystems, logical volumes, and guaranteed-rate I/O.

## What This Guide Contains

The types of disks, filesystems, and logical volumes covered in this guide are:

- SCSI disks. Systems that run IRIX 6.2 or later use only SCSI disks.

- The XFS filesystem. The XFS filesystem, a high-performance alternative to the earlier EFS filesystem developed by Silicon Graphics, was first released for IRIX 5.3.

- The Extent File System(EFS). The EFS filesystem, a filesystem developed by Silicon Graphics, was the filesystem used by IRIX for many years.

- XLV logical volumes. The XLV logical volume system, a high-performance logical volume system with many advanced features was developed by Silicon Graphics and released first for IRIX 5.3.

  | Note: This guide does not document administration of CXFS filesystems or XVM logical volumes. For information on CXFS filesystems, see the CXFS Version 2 Software Installation and Administration Guide and for information on XVM logical volumes see the XVM Volume Manager Administrator's Guide.

This guide is organized into chapters that provide reference information (the “concepts” chapters) and chapters that give procedures for performing disk and filesystem administration tasks. Appendices provide in-depth information about repairing inconsistent filesystems. These chapters and appendices are:

- Chapter 1, “Disk Concepts”, provides information about the structure of disks, disk partitioning, and disk partition device files.

- Chapter 2, “Performing Disk Administration Procedures”, describes disk administration tasks such as listing disks, initializing disks, modifying volume headers, repartitioning disks, creating device files, and adding new disks to systems.

- Chapter 3, “XLV Logical Volume Concepts”, describes the general concepts of logical volumes and the specifics of XLV logical volumes.

- Chapter 4, “Creating and Administering XLV Logical Volumes”, provides administration procedures for creating and administering XLV logical volumes and converting `lv` logical volumes (an older type of logical volume that is no longer supported) to XLV.

- Chapter 5, “Filesystem Concepts”, provides information about the IRIX filesystem layout, general filesystem concepts, details of the XFS filesystem types, and discussions of creating, mounting, checking, and growing filesystems.

- Chapter 6, “Creating and Growing Filesystems”, describes filesystem administration procedures such as making filesystems, mounting them, growing them, and converting from EFS to XFS.

- Chapter 7, “Maintaining Filesystems”, describes filesystem administration procedures that need to be performed routinely or on an as-needed basis, such as checking filesystems and managing disk usage when the amount of free disk space is low.

- Chapter 8, “System Administration for Guaranteed-Rate I/O”, provides information about guaranteed-rate I/O and the administration procedures required to support its use by applications.

- Appendix A, “EFS Filesystems”, provides information about EFS filesystems and their administration.

## Conventions Used in This Guide

These type conventions and symbols are used in this guide:

`command` |  | This fixed-space font denotes literal items (such as commands, files, routines, pathnames, signals, messages, programming language structures, and e-mail addresses) and items that appear on the screen.
variable |  | Italic typeface denotes variable entries and words or concepts being defined.
`user input` |  | This bold, fixed-space font denotes literal items that the user inters in interactive sessions. Output is shown in nonbold, fixed-space font.
[ ] |  | Brackets enclose optional portions of a command or directive line.
... |  | Ellipses indicate that a preceding element can be repeated.
`manpage`(x) |  | Man page section identifiers appear in parentheses after man page names.

When a procedure provided in this guide can also be performed using the Disk Manager in the System Toolchest or additional information on a topic is provided in the Personal System Administration Guide, a Tip describes the information you can find in that document. For example:

| Tip: You can use the Disk Manager in the System Toolchest to get information about the disks on a system. For instructions, see the “Checking Disk Setup Information” section in the Personal System Administration Guide.

When a procedure could result in the loss of files if not performed correctly or should be performed only by knowledgeable users, the procedure is preceded by a Caution. For example:

| Caution: The procedure in this section can result in the loss of data if it is not performed properly. It is recommended only for experienced IRIX system administrators.

Some features described in this guide are available only when software option products are purchased. These features and their option products are identified in Notes. For example:

| Note: The plexing feature of XLV, which enables the use of the optional plexes, is available only when you purchase the Disk Plexing Option software option.

## How to Use This Guide

IRIX Admin: Disks and Filesystems is written for system administrators and other knowledgeable IRIX users who need to perform administration tasks on their disks, filesystems, and logical volumes. It provides command line procedures for performing administration tasks; these tasks are most relevant to administering servers and workstations with many disks. Simple disk and filesystem administration using the graphical user interface provided by the Disk Manager is described in the Personal System Administration Guide.

Anyone with a basic knowledge of IRIX can use this guide to learn and perform basic disk and filesystem administration procedures. However, some procedures in this guide can result in loss of files on the system if the procedures are not performed correctly. These procedures should be performed by people who are:

- Familiar with IRIX filesystem administration procedures

- Experienced in disk repartitioning using `fx`

- Experienced in performing administration tasks from the shell in the miniroot environment provided by `inst`

- Familiar with filesystem backup concepts and procedures, particularly those using `dump`

A Caution paragraph appears at the beginning of each procedure that should be performed only by knowledgeable administrators. To learn more about system administration, see the IRIX Admin: System Configuration and Operation guide.

To use several features described in this guide, you must obtain FLEXlm licenses by purchasing separate software options. The features that require FLEXlm licenses are:

- The plexing feature of XLV logical volumes, which provides mirroring of disks up to four copies. This feature is provided by the Disk Plexing Option software option.

- Guaranteed-rate I/O. Guaranteed-rate I/O (GRIO) is a feature of IRIX that enables an application to request a fixed I/O rate and, if granted, be assured of receiving that rate. By default, the system allows four guaranteed-rate I/O streams. To obtain up to 40 streams, you must purchase the High Performance Guaranteed-Rate
  I/O—5-40 Streams software option. An unlimited number of streams is provided by the High Performance Guaranteed-Rate I/O—Unlimited Streams software option.

## Product Support

Silicon Graphics offers comprehensive product support and maintenance programs for its products. For information about using support services for IRIX and the other products described in this guide, refer to the release notes for IRIX and `eoe`.

## Additional Resources

For more information about disk management on IRIX, see these sources:

- The Personal System Administration Guide provides basic information on system administration of Silicon Graphics systems. Although it has not yet been updated to include information on XFS and XLV, it provides basic information on many system administration tasks.

- Online reference pages (man pages) on various disk information and management commands are included in the standard system software and can be viewed online using the `man` and `xman` commands or the Man Pages item on the Help menu of the System Toolchest.

- The CXFS Version 2 Software Installation and Administration Guide describes the administration of CXFS filesystems.

- The XVM Volume Manager Administrator's Guide describes the configuration and administration of XVM logical volumes using the XVM Volume Manager.

For more information on developing applications that access XFS filesystems, see these sources:

- Online reference pages for system calls and library routines relevant to XFS and GRIO are provided in the IRIS Developer's Option (IDO) software product.

- The REACT/Pro Programmer's Guide provides information about developing applications that use GRIO.

For instructions on loading the miniroot, see IRIX Admin: Software Installation and Licensing.

For information on acquiring and installing FLEXlm licenses that enable the Disk Plexing and High Performance Guaranteed-Rate I/O software options, see IRIX Admin: Software Installation and Licensing.

For additional information on changes in recent software releases of the software documented in this guide, see the release notes for these products:

- IRIX

- eoe

- NFS

- dev

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IRIX Admin Manual Set |  | Chapter 1. Disk Concepts