[
https://issues.apache.org/jira/browse/MAPREDUCE-3361?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13160969#comment-13160969
]
Ramkumar Vadali commented on MAPREDUCE-3361:
--------------------------------------------
It will also be nice to have this code be backwards compatible with existing
Reed-Solomon parity files. If there is an existing Reed-Solomon parity file,
the code can identify that by counting the number of parity blocks with the
expected number of Reed-Solomon parity files. This is doable because the
additional XOR parity blocks will increase the total number of parity blocks by
a deterministic number. Thus this code will be able to handle existing
Reed-Solomon parity files and will generate new files with additional XOR
blocks.
> 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.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators:
https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira
