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Hadoop, mail # user - Number of maps do not correspond to mapred.tasktracker.map.tasks.maximum


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Number of maps do not correspond to mapred.tasktracker.map.tasks.maximum
Saptarshi Guha 2009-09-07, 22:27
Hello,
I'm using Hadoop 0.21 and have mapred.tasktracker.map.task.max set to  
6. Yet despite there being 1000 tasks
only is being run (according to the web ui)(the corresponding one for  
reduce is 4)
 From the webui

ttempt_200909071242_0014_r_000000_0  RUNNING  9.76%
   attempt_200909071242_0014_r_000001_0  RUNNING  9.70%
   attempt_200909071242_0014_r_000002_0  RUNNING  9.73%
   attempt_200909071242_0014_r_000003_0  RUNNING  9.70%
   attempt_200909071242_0014_m_000295_0  RUNNING  0.00%

4 reduces, and only 1 map

Host  # running tasks  Max Map Tasks  Max Reduce Tasks  Failures  
Seconds since heartbeat
   tracker_acrux:localhost.localdomain/127.0.0.1:36144  acrux.edu  5  
6  4  0  0

Any reasons why? is it a problem with my Inputformat? I have 1000  
tasks of each length 1000.

I'm subclassing  Hadoop 0.21 mapreduce (not mapred) inputformats.

Thank you
Saptarshi