Managing RAID on Linux - Derek Vadala [142]
The image on the cover of Managing RAID on Linux is a logjam. Emma Colby designed the cover of this book, based on a series design by Hanna Dyer and Edie Freedman. The cover image is a 19th-century engraving from the Trades and Occupations collection of the Dover Pictorial Archive. Emma Colby produced the cover layout with QuarkXPress 4.1, using Adobe's ITC Garamond font.
David Futato designed the interior layout. The chapter opening images are from the Dover Pictorial Archive, Marvels of the New West: A Vivid Portrayal of the Stupendous Marvels in the Vast Wonderland West of the Missouri River, by William Thayer (The Henry Bill Publishing Co., 1888), and The Pioneer History of America: A Popular Account of the Heroes and Adventures, by Augustus Lynch Mason, A.M. (The Jones Brothers Publishing Company, 1884).
This book was converted to FrameMaker 5.5.6 by Joe Wizda, using a format conversion tool created by Erik Ray, Jason McIntosh, Neil Walls, and Mike Sierra that uses Perl and XML technologies. The text font is Linotype Birka; the heading font is Adobe Myriad Condensed; and the code font is LucasFont's TheSans Mono Condensed. The illustrations that appear in the book were produced by Robert Romano and Jessamyn Read, using Macromedia FreeHand 9 and Adobe Photoshop 6. The tip and warning icons were drawn by Christopher Bing.
Table of Contents
Preface
Overview of the Book
A Note About Architecture
Kernels
LILO
Prompts
Conventions Used in This Book
Comments and Questions
Acknowledgments
1. Introduction
RAID Terminology
Redundancy
Striping
The RAID Levels: An Overview
RAID-0: Striping
RAID-1: Mirroring
RAID-4: Dedicated Parity
RAID-5: Distributed Parity
Linear Mode
JBOD (Just a Bunch Of Disks)
RAID on Linux
Hardware Versus Software
2. Planning and Architecture
Hardware or Software?
Software (Kernel-Managed) RAID
Hardware
The RAID Levels: In Depth
RAID-0 (Striping)
Linear Mode
RAID-1 (Mirroring)
RAID-4
RAID-5
Hybrid Arrays
RAID Case Studies: What Should I Choose?
Case 1: HTTP Image Server
Case 2: Usenet News
Case 3: Home Use (Digital Audio, Video, and Images)
Case 4: The Acme Motion Picture Company
Case 5: Video on Demand
Disk Failures
Degraded Mode
Hot-Spares
Hot-Swap
Hardware Considerations
An Organizational Overview
Motherboards and the PCI Bus
I/O Channels
Disk Access Protocols
The AT Attachment (ATA) and Integrated Disk Electronics (IDE)
SCSI
SCSI Versus ATA
Other Disk Access Protocols
Choosing Hard Drives
Cases, Cables, and Connectors
Making Sense of It All
3. Getting Started: Building a Software RAID
Kernel Configuration
A Brief History Lesson
Kernel 2.4
Patching Older Kernels
Summary of Kernel Upgrades
Working with Software RAID
raidtools
mdadm
The RAID Superblock
Examining Arrays Using /proc/mdstat
Existing Arrays
Creating an Array
Partitioning with fdisk
Linear (Append) Mode
RAID-0 (Striping)
RAID-1 (Mirroring)
RAID-4 (Dedicated Parity)
RAID-5 (Distributed Parity)
Hybrid Arrays
Finishing Touches
The Next Step
4. Software RAID Reference
Kernel Options
Deprecated Kernel Options
md Block Special Files
/proc and Software RAID
/proc/mdstat
/proc/sys/dev/raid
raidtools
The /etc/raidtab File
raidtools Commands
mdadm
5. Hardware RAID
Choosing a RAID Controller
Motherboard and System Compatibility
Controller Memory
JBOD (Just a Bunch of Disks)
Software Considerations
Preparing Controllers and Disks
FreeDOS
General Configuration Issues
Controller Card BIOS
System Installation
RAID Autoconfiguration
Write Cache
Logical Drives
Controller Disk Spin-up
Mylex
The DAC960 Driver
Controller Setup
Managing Arrays
Adaptec
Adaptec I2O RAID Driver
The