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From "Subroto Sanyal (Commented) (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (MAPREDUCE-3473) Task failures shouldn't result in Job failures
Date Wed, 30 Nov 2011 05:31:44 GMT

    [ https://issues.apache.org/jira/browse/MAPREDUCE-3473?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13159834#comment-13159834

Subroto Sanyal commented on MAPREDUCE-3473:

*mapreduce.map.failures.maxpercent* and *mapreduce.reduce.failures.maxpercent* hold the percentage
of failure tolerance of number of Tasks for Job to handle.

Say in case a map fails and it comes under the tolerance limit then the output of the mapper
is lost(will not be considered for further computation). Same is with Reducer.

I suggest let user decide the this failure percentage and be ready for such data loss otherwise,
it will come to a surprise to user if the value is set to non-zero.

Further I feel there won't be any correct default non-zero value for these configurations.
These values depend on user scenarios/use-cases.
> Task failures shouldn't result in Job failures 
> -----------------------------------------------
>                 Key: MAPREDUCE-3473
>                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-3473
>             Project: Hadoop Map/Reduce
>          Issue Type: Improvement
>          Components: tasktracker
>    Affects Versions:, 0.23.0
>            Reporter: Eli Collins
> Currently some task failures may result in job failures. Eg a local TT disk failure seen
in TaskLauncher#run, TaskRunner#run, MapTask#run is visible to and can hang the JobClient,
causing the job to fail. Job execution should always be able to survive a task failure if
there are sufficient resources. 

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