IBM SG24-4576-00 guide

	Disk
	Controller

xxxxx xxxxx xxxxx xxxxx Parity Block 0

yyyyy yyyyy yyyyy yyyyy Parity

									Block n

	Disk 1		Disk 2		Disk 3		Disk	4	Disk 5
	xxxxx and yyyyy = Blocks belonging					to long		files

Figure 18. RAID-4 (Block Interleave Data Striping with One Parity Disk)

1.6.6.7 RAID-5 - Block Interleave Data Striping with Skewed Parity

The RAID-5 design tries to overcome all of these problems. Data is striped across the disks to ensure maximum read performance when accessing large files, and having the data striped in blocks improves the array′s performance in a transaction processing environment. Parity information is stored on the array to guard against data loss. Skewing is used to remove the bottleneck that is created by storing all the parity information on a single drive.



		Disk
		Controller

xxxxx xxxxx xxxxx xxxxx Parity Block 0

xxxxx xxxxx xxxxx Parity xxxxx

yyyyy yyyyy Parity yyyyy yyyyy

								Block n

	Disk 1		Disk 2	Disk 3		Disk	4	Disk 5
	xxxxx and yyyyy = Blocks belonging to long						files

Figure 19. RAID-5 (Block Interleave Data Striping with Skewed Parity)

Chapter 1. IBM PC Server Technologies 29

Image 44

IBM SG24-4576-00 manual RAID-5 Block Interleave Data Striping with Skewed Parity

Contents

IBM PC Server and Novell NetWare Integration Guide December First Edition December Take Note Abstract Contents Novell NetWare Installation IBM PC Server Family Overview Appendix A. Eisa Configuration File Appendix C. Configuring DOS CD-ROM Support Figures RAID NetFinity Network Driver Configuration Summary of RAID Performance Characteristics Tables Special Notices IBM VM/ESA Preface How This Document is Organized How to Order Itso Redbooks Related PublicationsInternational Technical Support Organization Publications Itso Redbooks on the World Wide Web WWW Acknowledgments Clock Rate IBM PC Server TechnologiesProcessors External Interfaces Processor Types Multiprocessing Memory Caches ∙ Write-Through Cache SMP Caching ∙ Write-Back Cache Memory Interleaving Shows SMP with dedicated secondary cache Dual Path Buses Two-Way Interleaved Memory Banks Scsi SynchroStream TechnologyCPU Standard Parity Memory Memory Error Detection and CorrectionError Correcting Code ECC Error Correcting Code-Parity Memory ECC-P ECC Memory Operation ECC on SIMMs EOS Memory Data 4 parity Bits for data Bits for ECC Memory Controller Bus Architectures Performance ImpactMemory Options and Speed ISA Bus Eisa BusMicro Channel Bus Data Streaming Micro Channel Basic Data Transfer 20 MBps PCI Bus Micro Channel Data Streaming Transfer 80 MBps Disk Subsystem Hard Disk Interfaces Scsi Technology ∙ SCSI-I and SCSI-II ∙ Common Command Set ∙ Tagged Command Queuing TCQ∙ Scatter/Gather ∙ Fast/Wide Devices and Controllers Scsi Adapters ∙ Synchronous versus Asynchronous ∙ IBM SCSI-2 Fast/Wide Streaming-RAID Adapter/A Hard Disk Drives Summary RAID Technology Mtbf RAID Classifications RAID Level Description RAID-0 Block Interleave Data Striping without Parity RAID-1 Disk Mirroring/Duplexing RAID-1 Enhanced Data Strip Mirroring Disk Controller Data BBBEEE FFF RAID-2 Bit Interleave Data Striping with Hamming Code RAID-2 Bit Interleave Data Striping with Hamming Code RAID-3 Bit Interleave Data Striping with Parity Disk RAID-4 Block Interleave Data Striping with One Parity Disk RAID-5 Block Interleave Data Striping with Skewed Parity RAID-4 Block Interleave Data Striping with One Parity Disk Summary of RAID Performance Characteristics Shared RAM Adapters RecommendationsLAN Subsystem Bus Master Adapters PeerMaster Technology Security Features Secure I/O Cables PasswordsTamper-Evident Cover Privileged-Access Password Secure Removable Media Unattended Start Mode Selectable Drive StartupSystems Management 1 DMI Communicating Service Layer Management Information Format MIF Component Interface CI SnmpManagement Interface MI Management Information Base MIB Snmp AgentSnmp Manager Traps ∙ System Information NetFinity ServicesNetFinity System Partition Access ServerGuard ServiceECC Configuration ∙ Serial Control Service NetFinity Manager ∙ Remote Systems Manager NetFinity Architecture End-Use dimension SystemViewDMI Support Interoperability with Other Management Tools Application dimension Data dimension SystemView Management Protocols Fault ToleranceManaged resource dimension Communication links NetWare SFTSFT III Server Roles IOEngines and Mirrored Server MS Engines NetWare Integration Guide IBM PC Server Technologies Uninterruptible Power Supply UPS APC PowerChute Flex Events NetWare Integration Guide IBM PC Server Family Overview Shows the products in relation to one another IBM PC Server Model Specifications IBM PC Server 0XT MXT IBM PC Server 320 Eisa IBM PC Server 320 MCA 0YT 0YV 0YR 0YS IBM PC Server 520 Eisa IBM PC Server 520 MCA 2ZS 4ZS Hardware Configuration PCI/ISA/EISA Setup Program Main Menu IDE Devices Video Bios ShadowAdvanced Menu Advanced Menu Boot Options Diskette Drive Error Advanced Menu Peripherals Integrated IDE adapter Select Security Enter password A r d w a r e Configuration Eisa Configuration Utility Do you want to configure your system now Y,N? Eisa Configuration Utility Step ISA IDE Change Settings Scsi Select Utility Program Scsi Bit 68pin Bit 50pin Low High Device Configuration Is disabled Host Adapter System Programs Scsi ID #9 Starting From the System Partition Backup/restore system program Update system programsStarting From the Reference Diskette Main Menu Options Set configuration Set featuresCopy an options diskette Test the computer Backup/Restore System Programs Menu Set Configuration MenuBackup the system diskettes Backup the system partition View configuration System Programs Set Configuration Menu Change configuration System Programs View Configuration Screen Backup configuration Restore configurationRun automatic configuration Display memory map Set and view Scsi device configuration Set Configuration Memory Map Set Features Menu Set Configuration Scsi Device Configuration Set Features Menu Set power-on password Change power-on password Remove power-on password Set unattended start modeSet privileged-access mode Change privileged-access password Remove privileged password Set unauthorized-access monitor∙ Normal keyboard ∙ Fast keyboard On page 97 will appear Set Power-On Features Screen Test the Computer Display revision levels Display system error logMore Utilities Menu Advanced Diagnostic Program Stand-alone utility informationSet and view system identification Set character font Advanced Diagnostic Menu Run the test one time Log or display the errors RAID Controller UtilityLow-Level Format Program Run the test continuously RAID Configuration Program Adapter Selection RAID Configuration Program Drive Information Drive Information Formatting the Disks Select Format drive Change RAID Parameters Panel for changing RAID parameters looks like Figure Defining a Hot-Spare Disk RAID Configuration Program Create/Delete Array Menu RAID Configuration Program Disk Array Creation Creating a Disk Array RAID Configuration Program Logical Drive Definition Defining Logical Drives RAID Configuration Program RAID level Selection RAID Configuration Program Size Definition Setting the Write Policy Backup/Restoring the ConfigurationInitializing the Array Select Change write policy Select Backup config. to diskette Select Restore config. from diskette Starting ServerGuide Novell NetWare InstallationServerGuide Overview ServerGuide Language ServerGuide Main Menu Installing NetWare 4.1 with ServerGuide Select Software InstallationSelect Novell NetWare Select United States Select Install NetWare Installing NetWare Configuring NetWare Configuring IBM NetFinity Partitioning the Hard Disk Reviewing Configuration Unlocking Programs Installing NetWare Directory Services NDS Case-sensitive Installing NetWare 3.12 with Diskettes Information Requested at Time of InstallationInstallation Files Hardware Requirements LAN Drivers Installation ProcedureDisk Drivers NetWare Installation Select Retain Current Disk Partition and then press Enter Type Load CSERVER.312IBMRAID Partition Information Volume Status Select System Options Bind IPX to Token Select Create STARTUP.NCF File Select Create AUTOEXEC.NCF File STARTUP.NCF File Installing NetWare 4.1 with the Original CD-ROM Select NetWare Server Installation and press Enter ∙ Simple Installation∙ Custom Installation Select Custom installation of NetWare 4.1 and press Enter Disk Driver Options Select Create NetWare disk partition Select Return to Previous Menu and press Enter New Volume Information Install NetWare Directory ServicesNDS Context for the Server Editing STARTUP.NCF File File Copy Status NetFinity Services for NetWare Installing NetFinity Services for NetWareInstalling with Diskettes on the NetWare Server System Requirements Type a name for your server Choose keyword number to edit Installing with Diskettes from a Workstation Search ADD SYSNETFIN\ Load Netfbase NetFinity Services for NetWare Network Driver Configuration Select Options Select Service Execution Alerts Starting NetFinity Installing from a Workstation RAID Administration for NetWare UtilityInstalling the Utility Hard Disk Failure Simulation Copying NLMs to the NetWare Server RAID Administration Utility Main Menu Simulating with a Hot Spare Drive Verifying Array Configuration Detecting the Disk Failure Disk Failure NetFinity RAID Service RAID Administration Recovery Message Changes in Array Configuration NetFinity New Hot Spare Drive Alert NetFinity RAID Service New Hot Spare Simulating without a Hot Spare Drive NetFinity RAID Service Verifying Configuration NetFinity Alert Log Last Event Message RAID Administration Rebuild Progress RAID Administration Verifying the Rebuild Status Performance Tuning Hardware Tuning General Performance Characteristics File Server Performance General Characteristics NetWare Integration Guide Differences in LAN Adapters Performance Analysis Tools DatagLANce NetWare Monitoring Tools MONITOR.NLM Set Command Monitor Utility Tuning NetWare SERVMAN.NLM Block Size and Cache Buffer Size NetWare SET Cache Buffer SIZE=VALUE SET Turbo FAT RE-USE Wait TIME=VALUE Block Size NetWareTurbo Fat Indexing Directory Caching SET Maximum Directory Cache BUFFERS=VALUESET Directory Cache Allocation Wait TIME=VALUE NetWare 3.12 SET Maximum File Cache Buffers = Value File CachingSET Minimum File Cache Buffers = Value Maximum Concurrent Disk Cache Writes SET Maximum Concurrent Disk Cache WRITES=VALUE Dirty Disk Cache Delay Time Spanning Volumes Over Multiple DrivesMultiple Volumes Immediate Purge of Files Enable Disk Read After Write Verify SET Enable Read After Write VERIFY=VALUENetwork Subsystem LAN Device Driver Efficiency Packet Size Packet Receive BuffersSET Maximum Physical Receive Packet Size = Value Recommendation Recommendation System Memory New Packet Receive Buffer Wait TimeNetWare 3.12 Memory Pools SET NEW Packet Receive Buffer Wait TIME=VALUE NetWare 4.1 System Memory Pools Calculating Server Memory Requirements Memory RequirementsSystem Processor Load Monitor -P System Board Memory Appendix A. Eisa Configuration FileSYS OFF On OFF OFF on Jumper Name W28 PCI IDE IRQ Default factory settings PNP OTH PCI MSD IRQ DMA 2F3h 400h Eisa Finding Compatibility Information on the World Wide Web 199 Finding Device Drivers on the World Wide Web Sample Compatibility Report Showing Ethernet LAN Adapters Finding Software Patches on the World Wide Web Appendix C. Configuring DOS CD-ROM Support Installing CD-ROM Support for PCI AdaptersInstalling CD-ROM Support for Adaptec Adapters Installing CD-ROM Support for Micro-Channel Adapters ∙ MSCDEX.EXE List of Abbreviations Itso Index Special Characters Numerics DMI Nvram RAID-0 RAID-1 Security TCP/IP Comments/Suggestions Itso Technical Bulletin EvaluationPlease answer the following questions Ibml Itso Technical Bulletin Evaluation RED000 SG24-4576-00 Ibml Figures Test CH3 Sgover NW41DD WRAID07 Raidadm Headings File References Servs CH1E Index Entries File References Tables Processing Options Imbed Trace