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https://issues.apache.org/jira/browse/MAPREDUCE-3361?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13145682#comment-13145682
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Scott Chen commented on MAPREDUCE-3361:
---------------------------------------

I think one thing we need to do is to refactor the raid.Encoder and 
raid.Decoder. So they are generic to any ErasureCode. That way we can easily 
add different codes to Raid.
                
> Ability to use SimpleRegeratingCode to fix missing blocks
> ---------------------------------------------------------
>
>                 Key: MAPREDUCE-3361
>                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-3361
>             Project: Hadoop Map/Reduce
>          Issue Type: Improvement
>          Components: contrib/raid
>            Reporter: dhruba borthakur
>            Assignee: dhruba borthakur
>
> ReedSolomon encoding (n, k) has n storage nodes and can tolerate n-k 
> failures. Regenerating a block needs to access k blocks. This is a problem 
> when n and k are large. Instead, we can use simple regenerating codes (n, k, 
> f) that does first does ReedSolomon (n,k) and then does XOR with f stripe 
> size. Then, a single disk failure needs to access only f nodes and f can be 
> very small.

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