Chapter 7: Managing Fault Tolerance

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Chapter 7Managing Fault Tolerance
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• Fault Tolerance
• Recovering from Hard Disk Failure

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RAID Systems

• Hardware and Software Implementation of RAID
• RAID 1 Mirror Sets
• RAID 5 Stripe Sets with Parity
• RAID 1 vs. RAID 5
• Implementing RAID 1 and RAID 5

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Hardware and Software Implementation of RAID
RAID 1
Disk mirroring
RAID 2
Disk striping with error-correction code (ECC)
RAID 3
Disk striping with ECC stored as parity
RAID 4
Disk striping large blocks parity stored on one
drive
RAID 5
Disk striping with parity distributed across
multiple drives
Software Implementations of RAID Supported by
Windows NT Server
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RAID 1 Mirror Sets
Disk 0
Disk 1
Ftdisk.sys
Fault Tolerance Driver
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RAID 5 Stripe Sets with Parity
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RAID 1 vs. RAID 5
Mirror Sets
Stripe Sets with Parity

• Supports FAT and NTFS

• Supports FAT and NTFS

• Can mirror system or boot partition

• Cannot stripe system or boot partition

• Requires two hard disks

• Requires minimum of three hard disks

• Has higher cost per megabyte(50 percent
  utilization)

• Has lower cost per megabyte

• Has good read and write performance

• Has moderate write performance
• Has excellent read performance

• Uses less system memory

• Requires more system memory

• Supports as many as 32 hard disks

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Implementing RAID 1 and RAID 5
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Recovering from Hard Disk Failure

• Regenerating a Stripe Set with Parity
• Recovering from a Mirror Set Failure
• Creating a Fault Tolerance Boot Disk
• Understanding ARC Paths

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Regenerating a Stripe Set with Parity
Disk Administrator
Partition Fault Tolerance Tools View
Options Help
Fault Tolerance
Regenerate
Disk 3
Disk 4
Disk 5
Disk 1
Disk 2
Parity
Parity Information
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Recovering from a Mirror Set Failure
Disk 0
Disk 1
C
D
E
Manual Break
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Creating a Fault Tolerance Boot Disk
Format a disk using Windows NT Server
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Copy the necessary files
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Boot.ini
Modify Boot.ini
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Test the boot disk
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Understanding ARC Paths
multi(0)disk(0)rdisk(1)partition(2)
No BIOS
multi(0)
scsi(0)
rdisk(0)
rdisk(1)
disk(0)
partition(1)
E
partition(1)
partition(1)
D
G
partition(2)
partition(2)
Windows NT Server