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Allen Wittenauer resolved MAPREDUCE-1521. ----------------------------------------- Resolution: Fixed > 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 > Fix For: 0.22.1 > > Attachments: MAPREDUCE-1521-0.20-yahoo.patch, > MAPREDUCE-1521-0.20-yahoo.patch, MAPREDUCE-1521-0.20-yahoo.patch, > MAPREDUCE-1521-0.20-yahoo.patch, MAPREDUCE-1521-0.20-yahoo.patch, > MAPREDUCE-1521-trunk.patch, resourceestimator-threshold.txt, > resourcestimator-overflow.txt > > > 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? -- This message was sent by Atlassian JIRA (v6.2#6252)