这是我的第一个so职位，所以请让我知道如果我错过了什么重要的。我是一个mahout/hadoop初学者，正在尝试构建一个分布式推荐引擎。
为了模拟在远程集群上的工作，我在我的机器上设置了hadoop，以便与ubuntuvm（使用virtualbox）通信，而ubuntuvm也位于安装了hadoop的机器上。这个设置似乎运行良好，我现在正在尝试运行mahout的'推荐工作'（非常！）作为测试的小型试验数据集。
输入包括 .csv 包含大约50个用户首选项的文件（保存在hadoop dfs上），格式如下： userID, itemID, preference ... 我的命令是：

hadoop jar /Users/MyName/src/trunk/core/target/mahout-core-0.8-SNAPSHOT-job.jar org.apache.mahout.cf.taste.hadoop.item.RecommenderJob -Dmapred.input.dir=/user/MyName/Recommendations/input/TestRatings.csv -Dmapred.output.dir=/user/MyName/Recommendations/output -s SIMILARITY_PEARSON_CORELLATION

哪里 TestRatings.csv 是包含首选项和 output 是所需的输出目录。
起初，作业看起来运行良好，我得到以下输出：

12/12/11 12:26:21 INFO common.AbstractJob: Command line arguments: {--booleanData=[false], --endPhase=[2147483647], --maxPrefsPerUser=[10], --maxPrefsPerUserInItemSimilarity=[1000], --maxSimilaritiesPerItem=[100], --minPrefsPerUser=[1], --numRecommendations=[10], --similarityClassname=[SIMILARITY_PEARSON_CORELLATION], --startPhase=[0], --tempDir=[temp]}
12/12/11 12:26:21 INFO common.AbstractJob: Command line arguments: {--booleanData=[false], --endPhase=[2147483647], --input=[/user/Naaman/Delphi/input/TestRatings.csv], --maxPrefsPerUser=[1000], --minPrefsPerUser=[1], --output=[temp/preparePreferenceMatrix], --ratingShift=[0.0], --startPhase=[0], --tempDir=[temp]}
12/12/11 12:26:21 INFO jvm.JvmMetrics: Initializing JVM Metrics with processName=JobTracker, sessionId=
12/12/11 12:26:21 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
12/12/11 12:26:22 INFO input.FileInputFormat: Total input paths to process : 1 
12/12/11 12:26:22 WARN snappy.LoadSnappy: Snappy native library not loaded
12/12/11 12:26:22 INFO mapred.JobClient: Running job: job_local_0001
12/12/11 12:26:22 INFO mapred.Task:  Using ResourceCalculatorPlugin : null
12/12/11 12:26:22 INFO mapred.MapTask: io.sort.mb = 100
12/12/11 12:26:22 INFO mapred.MapTask: data buffer = 79691776/99614720
12/12/11 12:26:22 INFO mapred.MapTask: record buffer = 262144/327680
12/12/11 12:26:22 INFO mapred.MapTask: Starting flush of map output
12/12/11 12:26:22 INFO compress.CodecPool: Got brand-new compressor
12/12/11 12:26:22 INFO mapred.MapTask: Finished spill 0
12/12/11 12:26:22 INFO mapred.Task: Task:attempt_local_0001_m_000000_0 is done. And is in the process of commiting
12/12/11 12:26:22 INFO mapred.LocalJobRunner:
12/12/11 12:26:22 INFO mapred.Task: Task 'attempt_local_0001_m_000000_0' done.
12/12/11 12:26:22 INFO mapred.Task:  Using ResourceCalculatorPlugin : null
12/12/11 12:26:22 INFO mapred.ReduceTask: ShuffleRamManager: MemoryLimit=1491035776, MaxSingleShuffleLimit=372758944
12/12/11 12:26:22 INFO compress.CodecPool: Got brand-new decompressor
12/12/11 12:26:22 INFO compress.CodecPool: Got brand-new decompressor
12/12/11 12:26:22 INFO compress.CodecPool: Got brand-new decompressor
12/12/11 12:26:22 INFO compress.CodecPool: Got brand-new decompressor
12/12/11 12:26:22 INFO compress.CodecPool: Got brand-new decompressor
12/12/11 12:26:22 INFO mapred.ReduceTask: attempt_local_0001_r_000000_0 Thread started: Thread for merging on-disk files
12/12/11 12:26:22 INFO mapred.ReduceTask: attempt_local_0001_r_000000_0 Thread started: Thread for merging in memory files
12/12/11 12:26:22 INFO mapred.ReduceTask: attempt_local_0001_r_000000_0 Thread waiting: Thread for merging on-disk files
12/12/11 12:26:22 INFO mapred.ReduceTask: attempt_local_0001_r_000000_0 Need another 1 map output(s) where 0 is already in progress
12/12/11 12:26:22 INFO mapred.ReduceTask: attempt_local_0001_r_000000_0 Thread started: Thread for polling Map Completion Events
12/12/11 12:26:22 INFO mapred.ReduceTask: attempt_local_0001_r_000000_0 Scheduled 0 outputs (0 slow hosts and0 dup hosts)
12/12/11 12:26:23 INFO mapred.JobClient:  map 100% reduce 0%
12/12/11 12:26:28 INFO mapred.LocalJobRunner: reduce > copy >
12/12/11 12:26:31 INFO mapred.LocalJobRunner: reduce > copy >
12/12/11 12:26:37 INFO mapred.LocalJobRunner: reduce > copy >

但最后三行无限期地重复（我留了一夜……），两行：

12/12/11 12:27:22 INFO mapred.ReduceTask: attempt_local_0001_r_000000_0 Need another 1 map output(s) where 0 is already in progress
12/12/11 12:27:22 INFO mapred.ReduceTask: attempt_local_0001_r_000000_0 Scheduled 0 outputs (0 slow hosts and0 dup hosts)

每十二行重复一次。
我不确定我的输入是否有问题，或者试验数据的微小尺寸是否把事情搞砸了。任何帮助和/或建议最好的方式去做这将不胜感激。
p、 我试着按照https://www.box.com/s/041rdjeh7sny128r2uki