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https://issues.apache.org/jira/browse/MAPREDUCE-6166?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Vinod Kumar Vavilapalli updated MAPREDUCE-6166:
-----------------------------------------------
Target Version/s: 2.7.0, 3.0.0 (was: 3.0.0, 2.7.0)
Fix Version/s: 2.6.1
Pulled this into 2.6.1. Ran compilation and TestFetcher before the push. Patch
applied cleanly.
> Reducers do not validate checksum of map outputs when fetching directly to
> disk
> -------------------------------------------------------------------------------
>
> Key: MAPREDUCE-6166
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-6166
> Project: Hadoop Map/Reduce
> Issue Type: Bug
> Components: mrv2
> Affects Versions: 2.6.0
> Reporter: Eric Payne
> Assignee: Eric Payne
> Labels: 2.6.1-candidate
> Fix For: 2.7.0, 2.6.1
>
> Attachments: MAPREDUCE-6166.v1.201411221941.txt,
> MAPREDUCE-6166.v2.201411251627.txt, MAPREDUCE-6166.v3.txt,
> MAPREDUCE-6166.v4.txt, MAPREDUCE-6166.v5.txt
>
>
> In very large map/reduce jobs (50000 maps, 2500 reducers), the intermediate
> map partition output gets corrupted on disk on the map side. If this
> corrupted map output is too large to shuffle in memory, the reducer streams
> it to disk without validating the checksum. In jobs this large, it could take
> hours before the reducer finally tries to read the corrupted file and fails.
> Since retries of the failed reduce attempt will also take hours, this delay
> in discovering the failure is multiplied greatly.
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