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Standard Raid Calculation explained
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Standard RAID 5, RAID 1, RAID 0 Explained

Parity Block Order.

All Raid systems Hardware or Software work the same way. Data block size and block order are setup when the Raid Array is first initialized.
  • Block size can be anything the Raid Controller has available
  • 32K= 64 sectors per block
  • 64K= 128 sector
  • 128K=256 sector etc..

Left Synchronous (Standard) Raid 5

Left Asynchronous Raid 5

Right Synchronous Raid 5

Right Asynchronous Raid 5

Raid 0


Raid Calculation for missing hard drive with Raid 5 parity.

missing raid element

calculated element

Calculating CRC (Parity)

CRC1 = A xor B xor C
CRC2 = D xor E xor F
CRC3 = G xor H xor I
CRC4 = J xor K xor L


Calculating missing Drive C
C = A xor B xor CRC1
H = G xor CRC3 xor I
K = CRC4 xor J xor L

Single drive failure is completely recoverable. If a second hard drive fails, the raid will crash and you will need to recover one of the two failed hard drives to recover your data. Call us immediately if your Raid is not accessible (866) 432-8291


Raid 1

Raid 1

Disk A & Disk B are mirrored to Disk B & Disk C. Single hard drive failure is completely recoverable. If Disk B & Disk C or Disk A & Disk D fail, you can still recover the data. Any other hard drive failure will require the recovery of at least one of the two failed hard drives. Call us immediately if your Raid is not accessible (866) 432-8291


Raid 0

Raid 0

Loss of one drive in a Raid 0 configuration is catastrophic and not recoverable unless the failed hard drive can be recovered. Call us immediately if your Raid is not accessible (866) 432-8291



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