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HP 226593-B21 Smart Array 5i Plus Controller and Battery Backed Write Cache En - Page 90

Advantages, Table C-1, Summary of RAID Methods

UPC - 720591665913

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Drive Arrays and Fault Tolerance Advantages The advantages of RAID 5 are that: • It has a high read performance. • No loss of data occurs if one physical drive fails. • More drive capacity is usable than with RAID 1+0 (parity information requires only the storage space equivalent to one physical drive). Disadvantages The disadvantages of RAID 5 are that: • It has a relatively low write performance. • Loss of data occurs if a second drive fails before data from the first failed drive is rebuilt. Table C-1 summarizes the important features of the different kinds of RAID described. The decision chart in Table C-2 may help you to determine which option is best for your situation. Table C-1: Summary of RAID Methods Alternative name Usable drive space* Usable drive space formula Minimum number of physical drives RAID 0 Striping (no fault tolerance) 100% n 1 RAID 1+0 Mirroring 50% n/2 2 RAID 5 Distributed Data Guarding 67% to 93% (n-1)/n 3 continued Compaq Smart Array 5i Plus Controller and Battery Backed Write Cache Enabler User Guide C-9

Section	Page
Compaq Smart Array 5i Plus Controller and Battery Backed Write Cache Enabler User Guide	1
Notice	2
Contents	3
About This Guide	7
Important Safety Information	7
Symbols on Equipment	7
Symbols in Text	8
Text Conventions	9
Related Documents	9
Getting Help	10
Compaq Technical Support	10
Compaq Website	10
Compaq Authorized Reseller	10
Reader’s Comments	11
Chapter 1: Features	12
Overview of Controller Features	12
Battery Backed Write Cache Enabler	13
Memory	15
Controller Interface	16
SCSI Support	16
Drive Array Technology	16
Fault Management Features	17
Chapter 2: Installation Overview	19
Chapter 3: Installing the Smart Array 5i Plus Controller and Battery Backed Write Cache Enabler	21
Chapter 4: Updating the System Firmware	23
Running System ROMPaq from the CD	24
Running System ROMPaq from Diskette	24
Creating a System ROMPaq Diskette from the CD	24
Creating a System ROMPaq Diskette from the SoftPaq File	24
Using the Diskette	25
Chapter 5: Updating the Controller Firmware	26
Running Options ROMPaq from the Smart Array Controller Support Software CD	27
Running Options ROMPaq from Diskettes	28
Creating Diskettes Using the Smart Array Controller Support Software CD	28
Creating Diskettes Using the SmartStart and Support Software CD	28
Creating Diskettes Using the SoftPaq File	29
Using the Diskettes	29
Updating the System Partition	30
Chapter 6: Configuring the System	32
Using RBSU	32
Using ORCA	34
Chapter 7: Configuring an Array	35
Using ORCA	37
Using ACU	38
Running ACU from CD	39
Running ACU while Online	39
ACU Screen Descriptions	40
Main Configuration Screen	40
Secondary Screens	44
Typical Manual Configuration Procedures in ACU	51
Creating a New Array	51
Expanding Array Capacity	55
Extending Logical Drive Capacity	58
Migrating RAID Level or Stripe Size	59
Using CPQONLIN	60
Running CPQONLIN	61
Automatic Configuration	61
Manual Configuration	62
Typical Manual Configuration Procedures in CPQONLIN	64
Creating a Custom Configuration for a New Array	64
Adding a Spare Drive	65
Configuring the New Logical Drive	65
Configuring the Controller Settings	65
Expanding an Array	67
Migrating RAID Level or Stripe Size	68
Chapter 8: Installing the Device Drivers	69
Using the Smart Array Controller Support Software CD	69
Using the SmartStart and Support Software CD	69
Updating the Compaq Insight Manager Agents	70
Appendix A: Regulatory Compliance Notices	71
Regulatory Compliance Identification Numbers	71
Federal Communications Commission Notice	71
Class A Equipment	72
Class B Equipment	72
Declaration of Conformity for Products Marked with the FCC Logo, United States Only	73
Modifications	73
Cables	74
Canadian Notice (Avis Canadien)	74
Class A Equipment	74
Class B Equipment	74
Mouse Compliance Statement	74
European Union Notice	75
Japanese Notice	76
Taiwanese Notice	76
Laser Device	77
Laser Safety Warnings	77
Compliance with CDRH Regulations	77
Compliance with International Regulations	77
Laser Product Label	78
Laser Information	78
Battery Replacement Notice	79
Appendix B: Electrostatic Discharge	80
Grounding Methods	81
Appendix C: Drive Arrays and Fault Tolerance	82
What Is a Drive Array?	82
Fault-Tolerance Methods	86
RAID 0—No Fault Tolerance	86
Advantages	86
Disadvantages	86
RAID 1+0—Drive Mirroring	87
Advantages	88
Disadvantages	89
RAID 5—Distributed Data Guarding	89
Advantages	90
Disadvantages	90
Other Fault-Tolerance Options	92
Appendix D: Hard Drive Installation and Replacement	93
General Information About Hard Drive Failure	93
Recognizing Drive Failure	94
Compromised Fault Tolerance	97
Procedure to Attempt Recovery	97
Automatic Data Recovery	98
Failure of Automatic Data Recovery	98
General Aspects of Drive Replacement	99
Drive Failure During Rebuild	100
Minimizing Fatal System Errors During Rebuild	100
Moving Drives and Arrays	101
Upgrading Disk Drive Capacity	103
Expanding and Extending Capacity	103
Appendix E: Probability of Logical Drive Failure	105
Appendix F: POST Error Messages	107
Appendix G: Questions and Answers	123
Glossary	126