About This Guide

The RAID System Administration Guide describes configuration, maintenance, and error recovery procedures for Silicon Graphics'® RAID (Redundant Array of Inexpensive Disks) product. The IRIX™ 5.0.1 version of the RAID device driver and the RAID administrative utility, raid(1M), are documented.

How to Use This Guide

Read “About This Guide” to learn what hardware and software is documented in this guide, what the prerequisites are for using RAID, about the documentation conventions in this guide, about product support for Silicon Graphics products, and where to go for more information about RAID.

Read Chapter 1, “Introduction to RAID,” to learn RAID basics: what it is, the similarities and differences between RAID and non-RAID disks, the configuration options, the RAID LEDs, and RAID failure prediction and recovery features.

Turn to Chapter 2, “Formatting a RAID,” to learn how to format a new RAID and reformat an existing RAID.

Chapter 3, “Routine Maintenance Tasks,” covers a variety of tasks that system administrators occasionally may need to perform during normal operation of a RAID.

Chapter 4, “Recovering after a Disk Warning or Failure,” describes how to replace a disk drive in a RAID unit after a predictive warning or a failure. It includes instructions for rebuilding a new disk drive with the same data as the replaced disk drive.

Chapter 5, “Error Messages,” contains lists of RAID error messages and suggested recovery procedures.

Appendix A, “Programming Hints,” contains tips for application developers on getting maximum I/O performance from a RAID.

Many readers will not need this entire guide. The chapters you need depend upon your role:

  • System Administrator

    System administrators are the primary audience of this guide. The entire guide except for Appendix A explains configuration, routine maintenance, and error recovery procedures that are likely to be performed by system administrators.

  • System Support Engineer

    System Support Engineers can find the procedure for formatting a RAID in Chapter 2.

  • Application Developer

    Application developers should read Chapter 1 to learn about the RAID configuration options that affect the performance of their applications and Appendix A for information about optimizing I/O in applications that read and write data on RAIDs.

This guide assumes that you know how to become superuser, get disk controller and unit numbers from hinv(1M), and how to make a file system on a disk with mkfs(1M).

Hardware and Software Requirements

RAID is supported on workstations and servers that have fast and wide SCSI buses. This includes CHALLENGE™ L, CHALLENGE XL, POWER CHALLENGE L, POWER CHALLENGE XL, Onyx™ Deskside, and Onyx Rack.

This guide applies only to RAID units manufactured by Silicon Graphics. The commands and procedures documented in this guide cannot be used when disk drives, RAID controllers, or RAID unit enclosures purchased from vendors other than Silicon Graphics are used, even when those parts appear to be identical to the ones used in RAID units purchased from Silicon Graphics.

Systems with one or more RAIDs must have a non-RAID system disk.

RAID requires IRIX Release 5.0.1 or later. The subsystem eoe1.sw.unix contains all of the files needed for RAID.

Documentation Conventions

To distinguish between physical disks and what appears to IRIX to be a disk, this guide uses the following terms:

disk 

one or more physical disk drives that appear to IRIX as a single disk

disk drive 

a single disk hardware unit

RAID 

the array of five disk drives that to IRIX appear as a single disk of type RAID

RAID unit 

the RAID hardware including five disk drives, a controller, a backplane, and an enclosure

Three terms are used to describe the states of RAIDs and/or their disk drives:

operational 

The RAID unit is operating normally.

failed 

The RAID unit or a disk drive is not responding to commands, or it is responding but is not operating properly.

down 

The RAID unit or a disk drive has failed or is not operating because it has been manually shut down with the raid –d command.

This guide uses these font conventions:

italics 

Italics are used for command and manual page names, file names, variables, and the names of inst(1M) products and subsystems.

typewriter 

Typewriter font is used for examples of command output that is displayed in windows on your monitor.

bold typewriter 


Bold typewriter is used for commands and text that you are to type literally.

Product Support

Silicon Graphics provides a comprehensive product support and maintenance program for its products. For further information in the United States and Canada, contact the Technical Assistance Center at 1-800-800-4SGI. Elsewhere, contact your local service provider.

For More Information

For more information about RAID and disk management on IRIX, see the following sources:

  • The University of California at Berkeley report on RAID:

    D. Patterson, G. Garth, R. Katz, “A Case for Redundant Arrays of Inexpensive Disks (RAID),” University of California, Berkeley, Report No. UCB/CSD/87/391, December, 1987.

  • The IRIX Advanced Site and Server Administration Guide

  • IRIX manual pages on the raid administrative program and the RAID device driver:

    raid(1M), usraid(7)

  • IRIX manual pages on various disk information and management tools:

    dvhtool(1M), fx(1M), hinv(1M), mkfs(1M), mklv(1M), sar(1)