我在大约 500 个节点的集群上运行 Hadoop 版本 1.0.0。我的工作有大约 3000 个 map 任务和 10 个 reduce 任务。地图任务在大约 4 小时后完成（如预期的那样）。每个reduce任务都在不久之后完成，结果都在我的输出目录中可用。但是，jobtracker 认为某些 map 任务失败并开始重新执行它们。正在执行和挂起的 reduce 任务的数量保持为零。最终大约 8 小时后，这些地图任务中的最后一个最终成功完成，并且该作业被标记为成功完成。
有任何想法吗？？？
以下是部分jobtracker日志文件的摘录：
// map tasks all complete, eg:
2013-05-20 10:50:59,742 INFO org.apache.hadoop.mapred.JobInProgress:
Task 'attempt_201305131710_0007_m_000430_0' has completed task_201305131710_0007_m_000430 successfully.
//reduce tasks all complete:
2013-05-20 13:38:34,040 INFO org.apache.hadoop.mapred.JobInProgress: Task 'attempt_201305131710_0007_r_000009_0' has completed task_201305131710_0007_r_000009 successfully.
2013-05-20 13:38:34,142 INFO org.apache.hadoop.mapred.JobInProgress:
Task 'attempt_201305131710_0007_r_000004_0' has completed task_201305131710_0007_r_000004 successfully.
2013-05-20 13:38:34,204 INFO org.apache.hadoop.mapred.JobInProgress:
Task 'attempt_201305131710_0007_r_000008_0' has completed task_201305131710_0007_r_000008 successfully.
2013-05-20 13:38:34,745 INFO org.apache.hadoop.mapred.JobInProgress:
Task 'attempt_201305131710_0007_r_000002_0' has completed task_201305131710_0007_r_000002 successfully.
2013-05-20 13:38:35,521 INFO org.apache.hadoop.mapred.JobInProgress:
Task 'attempt_201305131710_0007_r_000003_0' has completed task_201305131710_0007_r_000003 successfully.
2013-05-20 13:38:36,196 INFO org.apache.hadoop.mapred.JobInProgress:
Task 'attempt_201305131710_0007_r_000007_0' has completed task_201305131710_0007_r_000007 successfully.
2013-05-20 13:38:36,276 INFO org.apache.hadoop.mapred.JobTracker: Adding tracker tracker_HN301-1657.labs.edu.au:127.0.0.1/127.0.0.1:1295 to host HN301-1657.labs.edu.au
2013-05-20 13:38:36,469 INFO org.apache.hadoop.mapred.JobInProgress:
Task 'attempt_201305131710_0007_r_000005_0' has completed task_201305131710_0007_r_000005 successfully.
2013-05-20 13:38:36,598 INFO org.apache.hadoop.mapred.JobInProgress:
Task 'attempt_201305131710_0007_r_000006_0' has completed task_201305131710_0007_r_000006 successfully.
2013-05-20 13:38:36,612 INFO org.apache.hadoop.mapred.JobInProgress:
Task 'attempt_201305131710_0007_r_000000_0' has completed task_201305131710_0007_r_000000 successfully.
2013-05-20 13:38:40,388 INFO org.apache.hadoop.mapred.JobInProgress:
Task 'attempt_201305131710_0007_r_000001_0' has completed task_201305131710_0007_r_000001 successfully.
2013-05-20 13:44:12,795 INFO org.apache.hadoop.mapred.JobTracker: Lost tracker 'tracker_HN301-1657.labs.edu.au:127.0.0.1/127.0.0.1:3896'
//As the reduce tasks are reporting success, the job tracker detects that one of the job trackers has died and so restarts it.
//Each of the jobs previously completed successfully by that task tracker are then reexecuted
2013-05-20 13:44:12,795 INFO org.apache.hadoop.mapred.TaskInProgress: Error from attempt_201305131710_0007_m_000430_0: Lost task tracker: tracker_HN301-1657.labs.edu.au:127.0.0.1/127.0.0.1:3896
2013-05-20 13:44:12,795 INFO org.apache.hadoop.mapred.TaskInProgress: Error from attempt_201305131710_0007_m_000571_0: Lost task tracker: tracker_HN301-1657.labs.edu.au:127.0.0.1/127.0.0.1:3896
2013-05-20 13:44:12,796 INFO org.apache.hadoop.mapred.TaskInProgress: Error from attempt_201305131710_0007_m_001612_0: Lost task tracker: tracker_HN301-1657.labs.edu.au:127.0.0.1/127.0.0.1:3896
2013-05-20 13:44:12,796 INFO org.apache.hadoop.mapred.TaskInProgress: Error from attempt_201305131710_0007_m_001629_0: Lost task tracker: tracker_HN301-1657.labs.edu.au:127.0.0.1/127.0.0.1:3896
2013-05-20 13:44:12,796 INFO org.apache.hadoop.mapred.TaskInProgress: Error from attempt_201305131710_0007_m_001892_0: Lost task tracker: tracker_HN301-1657.labs.edu.au:127.0.0.1/127.0.0.1:3896
2013-05-20 13:44:12,796 INFO org.apache.hadoop.mapred.TaskInProgress: Error from attempt_201305131710_0007_m_002424_0: Lost task tracker: tracker_HN301-1657.labs.edu.au:127.0.0.1/127.0.0.1:3896
2013-05-20 13:44:12,796 INFO org.apache.hadoop.mapred.TaskInProgress: Error from attempt_201305131710_0007_m_002437_0: Lost task tracker: tracker_HN301-1657.labs.edu.au:127.0.0.1/127.0.0.1:3896
2013-05-20 13:44:12,796 INFO org.apache.hadoop.mapred.TaskInProgress: Error from attempt_201305131710_0007_m_002696_0: Lost task tracker: tracker_HN301-1657.labs.edu.au:127.0.0.1/127.0.0.1:3896
2013-05-20 13:44:12,796 INFO org.apache.hadoop.mapred.TaskInProgress: Error from attempt_201305131710_0007_m_003130_0: Lost task tracker: tracker_HN301-1657.labs.edu.au:127.0.0.1/127.0.0.1:3896
2013-05-20 13:44:12,796 INFO org.apache.hadoop.mapred.TaskInProgress: Error from attempt_201305131710_0007_m_003149_0: Lost task tracker: tracker_HN301-1657.labs.edu.au:127.0.0.1/127.0.0.1:3896
2013-05-20 13:44:12,796 INFO org.apache.hadoop.mapred.TaskInProgress: Error from attempt_201305131710_0007_m_003187_0: Lost task tracker: tracker_HN301-1657.labs.edu.au:127.0.0.1/127.0.0.1:3896
2013-05-20 13:44:12,797 INFO org.apache.hadoop.mapred.TaskInProgress: Error from attempt_201305131710_0007_m_003275_0: Lost task tracker: tracker_HN301-1657.labs.edu.au:127.0.0.1/127.0.0.1:3896
2013-05-20 13:44:12,797 INFO org.apache.hadoop.mapred.TaskInProgress: Error from attempt_201305131710_0007_m_003358_0: Lost task tracker: tracker_HN301-1657.labs.edu.au:127.0.0.1/127.0.0.1:3896
2013-05-20 13:44:12,797 INFO org.apache.hadoop.mapred.TaskInProgress: Error from attempt_201305131710_0007_m_003437_0: Lost task tracker: tracker_HN301-1657.labs.edu.au:127.0.0.1/127.0.0.1:3896
2013-05-20 13:44:12,797 INFO org.apache.hadoop.mapred.TaskInProgress: Error from attempt_201305131710_0007_m_003451_0: Lost task tracker: tracker_HN301-1657.labs.edu.au:127.0.0.1/127.0.0.1:3896
2013-05-20 13:44:12,797 INFO org.apache.hadoop.mapred.TaskInProgress: Error from attempt_201305131710_0007_m_003478_0: Lost task tracker: tracker_HN301-1657.labs.edu.au:127.0.0.1/127.0.0.1:3896
2013-05-20 13:44:12,797 INFO org.apache.hadoop.mapred.TaskInProgress: Error from attempt_201305131710_0007_m_003506_0: Lost task tracker: tracker_HN301-1657.labs.edu.au:127.0.0.1/127.0.0.1:3896
2013-05-20 13:44:12,797 INFO org.apache.hadoop.mapred.TaskInProgress: Error from attempt_201305131710_0010_m_000021_0: Lost task tracker: tracker_HN301-1657.labs.edu.au:127.0.0.1/127.0.0.1:3896
2013-05-20 13:44:12,797 INFO org.apache.hadoop.mapred.JobTracker: Removing task 'attempt_201305131710_0010_m_000021_0'
2013-05-20 13:44:12,797 INFO org.apache.hadoop.mapred.JobTracker: Removing task 'attempt_201305131710_0007_m_000430_0'
2013-05-20 13:44:12,797 INFO org.apache.hadoop.mapred.JobTracker: Removing task 'attempt_201305131710_0007_m_000571_0'
2013-05-20 13:44:12,797 INFO org.apache.hadoop.mapred.JobTracker: Removing task 'attempt_201305131710_0007_m_001612_0'
2013-05-20 13:44:12,797 INFO org.apache.hadoop.mapred.JobTracker: Removing task 'attempt_201305131710_0007_m_001629_0'
2013-05-20 13:44:12,797 INFO org.apache.hadoop.mapred.JobTracker: Removing task 'attempt_201305131710_0007_m_001892_0'
2013-05-20 13:44:12,797 INFO org.apache.hadoop.mapred.JobTracker: Removing task 'attempt_201305131710_0007_m_002424_0'
2013-05-20 13:44:12,797 INFO org.apache.hadoop.mapred.JobTracker: Removing task 'attempt_201305131710_0007_m_002437_0'
2013-05-20 13:44:12,797 INFO org.apache.hadoop.mapred.JobTracker: Removing task 'attempt_201305131710_0007_m_002696_0'
2013-05-20 13:44:12,797 INFO org.apache.hadoop.mapred.JobTracker: Removing task 'attempt_201305131710_0007_m_003130_0'
2013-05-20 13:44:12,797 INFO org.apache.hadoop.mapred.JobTracker: Removing task 'attempt_201305131710_0007_m_003149_0'
2013-05-20 13:44:12,797 INFO org.apache.hadoop.mapred.JobTracker: Removing task 'attempt_201305131710_0007_m_003187_0'
2013-05-20 13:44:12,797 INFO org.apache.hadoop.mapred.JobTracker: Removing task 'attempt_201305131710_0007_m_003275_0'
2013-05-20 13:44:12,797 INFO org.apache.hadoop.mapred.JobTracker: Removing task 'attempt_201305131710_0007_m_003358_0'
2013-05-20 13:44:12,797 INFO org.apache.hadoop.mapred.JobTracker: Removing task 'attempt_201305131710_0007_m_003437_0'
2013-05-20 13:44:12,797 INFO org.apache.hadoop.mapred.JobTracker: Removing task 'attempt_201305131710_0007_m_003451_0'
2013-05-20 13:44:12,797 INFO org.apache.hadoop.mapred.JobTracker: Removing task 'attempt_201305131710_0007_m_003478_0'
2013-05-20 13:44:12,797 INFO org.apache.hadoop.mapred.JobTracker: Removing task 'attempt_201305131710_0007_m_003506_0'
2013-05-20 13:44:12,917 INFO org.apache.hadoop.mapred.JobTracker: Adding task (TASK_CLEANUP) 'attempt_201305131710_0010_m_000021_0' to tip task_201305131710_0010_m_000021, for tracker 'tracker_HN301-1654.labs.edu.au:127.0.0.1/127.0.0.1:1100'
2013-05-20 13:44:13,760 INFO org.apache.hadoop.mapred.JobInProgress: Choosing a failed task task_201305131710_0007_m_000430
2013-05-20 13:44:13,761 INFO org.apache.hadoop.mapred.JobTracker: Adding task (MAP) 'attempt_201305131710_0007_m_000430_1' to tip task_201305131710_0007_m_000430, for tracker 'tracker_ZC329-0001.labs.edu.au:127.0.0.1/127.0.0.1:1113'