我在 Amazon Elastic MapReduce 集群上从命令行运行 Mahout 0.6，试图对大约 1500 个短文档进行树冠集群，并且作业不断失败，并显示“错误：Java 堆空间”消息。
根据这里和其他地方以前的问题，我已经调高了我能找到的每个内存旋钮：
conf/hadoop-env.sh：在小型实例上将所有堆空间设置为高达 1.5GB，在大型实例上甚至为 4GB。
conf/mapred-site.xml：添加 mapred.{map, reduce}.child.java.opts 属性，并将其值设置为 -Xmx4000m
$MAHOUT_HOME/bin/mahout：增加 JAVA_HEAP_MAX 并将 MAHOUT_HEAPSIZE 设置为 6GB（在大型实例上）。
而且问题一直存在。我一直在反对这个问题太久了——有人有什么建议吗？
完整的命令和输出看起来像这样（在大型实例集群上运行，希望它能缓解问题）：
hadoop@ip-10-80-202-112:~$ mahout-distribution-0.6/bin/mahout canopy -i sparse-data/2010/tf-vectors -o canopy-out/2010 -dm org.apache.mahout.common.distance.TanimotoDistanceMeasure -ow -t1 0.5 -t2 0.005 -cl
run with heapsize 6000
-Xmx6000m
MAHOUT_LOCAL is not set; adding HADOOP_CONF_DIR to classpath.
Running on hadoop, using HADOOP_HOME=/home/hadoop
No HADOOP_CONF_DIR set, using /home/hadoop/conf
MAHOUT-JOB: /home/hadoop/mahout-distribution-0.6/mahout-examples-0.6-job.jar
12/04/29 19:50:23 INFO common.AbstractJob: Command line arguments: {--clustering=null, --distanceMeasure=org.apache.mahout.common.distance.TanimotoDistanceMeasure, --endPhase=2147483647, --input=sparse-data/2010/tf-vectors, --method=mapreduce, --output=canopy-out/2010, --overwrite=null, --startPhase=0, --t1=0.5, --t2=0.005, --tempDir=temp}
12/04/29 19:50:24 INFO common.HadoopUtil: Deleting canopy-out/2010
12/04/29 19:50:24 INFO canopy.CanopyDriver: Build Clusters Input: sparse-data/2010/tf-vectors Out: canopy-out/2010 Measure: org.apache.mahout.common.distance.TanimotoDistanceMeasure@a383118 t1: 0.5 t2: 0.0050
12/04/29 19:50:24 INFO mapred.JobClient: Default number of map tasks: null
12/04/29 19:50:24 INFO mapred.JobClient: Setting default number of map tasks based on cluster size to : 24
12/04/29 19:50:24 INFO mapred.JobClient: Default number of reduce tasks: 1
12/04/29 19:50:25 INFO mapred.JobClient: Setting group to hadoop
12/04/29 19:50:25 INFO input.FileInputFormat: Total input paths to process : 1
12/04/29 19:50:25 INFO mapred.JobClient: Running job: job_201204291846_0004
12/04/29 19:50:26 INFO mapred.JobClient: map 0% reduce 0%
12/04/29 19:50:45 INFO mapred.JobClient: map 27% reduce 0%
[ ... Continues fine until... ]
12/04/29 20:05:54 INFO mapred.JobClient: map 100% reduce 99%
12/04/29 20:06:12 INFO mapred.JobClient: map 100% reduce 0%
12/04/29 20:06:20 INFO mapred.JobClient: Task Id : attempt_201204291846_0004_r_000000_0, Status : FAILED
Error: Java heap space
12/04/29 20:06:41 INFO mapred.JobClient: map 100% reduce 33%
12/04/29 20:06:44 INFO mapred.JobClient: map 100% reduce 68%
[.. REPEAT SEVERAL ITERATIONS, UNITL...]
12/04/29 20:37:58 INFO mapred.JobClient: map 100% reduce 0%
12/04/29 20:38:09 INFO mapred.JobClient: Job complete: job_201204291846_0004
12/04/29 20:38:09 INFO mapred.JobClient: Counters: 23
12/04/29 20:38:09 INFO mapred.JobClient: Job Counters
12/04/29 20:38:09 INFO mapred.JobClient: Launched reduce tasks=4
12/04/29 20:38:09 INFO mapred.JobClient: SLOTS_MILLIS_MAPS=94447
12/04/29 20:38:09 INFO mapred.JobClient: Total time spent by all reduces waiting after reserving slots (ms)=0
12/04/29 20:38:09 INFO mapred.JobClient: Total time spent by all maps waiting after reserving slots (ms)=0
12/04/29 20:38:09 INFO mapred.JobClient: Rack-local map tasks=1
12/04/29 20:38:09 INFO mapred.JobClient: Launched map tasks=1
12/04/29 20:38:09 INFO mapred.JobClient: Failed reduce tasks=1
12/04/29 20:38:09 INFO mapred.JobClient: SLOTS_MILLIS_REDUCES=23031
12/04/29 20:38:09 INFO mapred.JobClient: FileSystemCounters
12/04/29 20:38:09 INFO mapred.JobClient: HDFS_BYTES_READ=24100612
12/04/29 20:38:09 INFO mapred.JobClient: FILE_BYTES_WRITTEN=49399745
12/04/29 20:38:09 INFO mapred.JobClient: File Input Format Counters
12/04/29 20:38:09 INFO mapred.JobClient: Bytes Read=24100469
12/04/29 20:38:09 INFO mapred.JobClient: Map-Reduce Framework
12/04/29 20:38:09 INFO mapred.JobClient: Map output materialized bytes=49374728
12/04/29 20:38:09 INFO mapred.JobClient: Combine output records=0
12/04/29 20:38:09 INFO mapred.JobClient: Map input records=409
12/04/29 20:38:09 INFO mapred.JobClient: Physical memory (bytes) snapshot=2785939456
12/04/29 20:38:09 INFO mapred.JobClient: Spilled Records=409
12/04/29 20:38:09 INFO mapred.JobClient: Map output bytes=118596530
12/04/29 20:38:09 INFO mapred.JobClient: CPU time spent (ms)=83190
12/04/29 20:38:09 INFO mapred.JobClient: Total committed heap usage (bytes)=2548629504
12/04/29 20:38:09 INFO mapred.JobClient: Virtual memory (bytes) snapshot=4584386560
12/04/29 20:38:09 INFO mapred.JobClient: Combine input records=0
12/04/29 20:38:09 INFO mapred.JobClient: Map output records=409
12/04/29 20:38:09 INFO mapred.JobClient: SPLIT_RAW_BYTES=143
Exception in thread "main" java.lang.InterruptedException: Canopy Job failed processing sparse-data/2010/tf-vectors
at org.apache.mahout.clustering.canopy.CanopyDriver.buildClustersMR(CanopyDriver.java:349)
at org.apache.mahout.clustering.canopy.CanopyDriver.buildClusters(CanopyDriver.java:236)
at org.apache.mahout.clustering.canopy.CanopyDriver.run(CanopyDriver.java:145)
at org.apache.mahout.clustering.canopy.CanopyDriver.run(CanopyDriver.java:109)
at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:65)
at org.apache.mahout.clustering.canopy.CanopyDriver.main(CanopyDriver.java:61)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.hadoop.util.ProgramDriver$ProgramDescription.invoke(ProgramDriver.java:68)
at org.apache.hadoop.util.ProgramDriver.driver(ProgramDriver.java:139)
at org.apache.mahout.driver.MahoutDriver.main(MahoutDriver.java:188)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.hadoop.util.RunJar.main(RunJar.java:156)