[jira] [Updated] (MAPREDUCE-6166) Reducers do not catch bad map output transfers during shuffle if data shuffled directly to disk

["Eric Payne (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/MAPREDUCE-6166?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Eric Payne updated MAPREDUCE-6166:
----------------------------------
    Attachment: MAPREDUCE-6166.v3.txt

[~jira.shegalov], your comments outlined in https://issues.apache.org/jira/browse/MAPREDUCE-6166?focusedCommentId=14225864&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-14225864 have been included in the attached patch (MAPREDUCE-6166.v3.txt). This patch is using {{readWithChecksum}}.

> Reducers do not catch bad map output transfers during shuffle if data shuffled 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
>         Attachments: MAPREDUCE-6166.v1.201411221941.txt, MAPREDUCE-6166.v2.201411251627.txt, MAPREDUCE-6166.v3.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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