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raid5

wolfric · 2010-06-22 18:41:43

How a stripe of data be recovered by the parity stripe and 2 of the others? So let's say you loose disk 1. You've now lost A1. You have A2,A3 and Ap. To me it seems like having to try brute forcing a file out of a hash.

22-06-2010 6:41pm

#1

wolfric

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How a stripe of data be recovered by the parity stripe and 2 of the others?

So let's say you loose disk 1. You've now lost A1. You have A2,A3 and Ap.

To me it seems like having to try brute forcing a file out of a hash.

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#2 22-06-2010 7:34pm

Voodu Child

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The parity data is generated using an XOR comparison.

If one block of data is missing you can regenerate it by XORing the others. Thats just an inherent propery of the XOR operation.

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#3 22-06-2010 9:38pm

wolfric

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Thanks did a quick search and found this. Good detailed read in case anyone's interested.

http://www.scottklarr.com/topic/23/how-raid-5-really-works/

Cheers

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