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https://issues.apache.org/jira/browse/MAPREDUCE-1521?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Mahadev konar updated MAPREDUCE-1521:
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Attachment: MAPREDUCE-1521-0.20-yahoo.patch
this patch adds some diagnostic information for the users on why the job
failed. I am still adding a junit test for this patch. again this patch is for
yahoo 0.20. Will upload a patch for trunk soon.
> Protection against incorrectly configured reduces
> -------------------------------------------------
>
> Key: MAPREDUCE-1521
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-1521
> Project: Hadoop Map/Reduce
> Issue Type: Improvement
> Components: jobtracker
> Reporter: Arun C Murthy
> Assignee: Mahadev konar
> Priority: Critical
> Fix For: 0.22.0
>
> Attachments: MAPREDUCE-1521-0.20-yahoo.patch,
> MAPREDUCE-1521-0.20-yahoo.patch
>
>
> We've seen a fair number of instances where naive users process huge
> data-sets (>10TB) with badly mis-configured #reduces e.g. 1 reduce.
> This is a significant problem on large clusters since it takes each attempt
> of the reduce a long time to shuffle and then run into problems such as local
> disk-space etc. Then it takes 4 such attempts.
> Proposal: Come up with heuristics/configs to fail such jobs early.
> Thoughts?
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