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Hadoop, mail # user - Problem with MR job


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Problem with MR job
George Kousiouris 2011-09-21, 13:58

Hi all,

We are trying to run a mahout job in a hadoop cluster, but we keep
getting the same status. The job passes the initial mahout stages and
when it comes to be executed as a MR job, it seems to be stuck at 0%
progress. Through the UI we see that it is submitted but not running.
After a while it gets killed. In the logs the error shown is this one:

2011-09-21 07:47:50,507 INFO org.apache.hadoop.mapred.JobTracker:
problem cleaning system directory:
hdfs://master/var/lib/hadoop-0.20/cache/hdfs/mapred/system
org.apache.hadoop.ipc.RemoteException:
org.apache.hadoop.hdfs.server.namenode.SafeModeException: Cannot create
directory /var/lib/hadoop-0.20/cache/hdfs/mapred/system. Name nod$
The reported blocks 0 needs additional 12 blocks to reach the threshold
0.9990 of total blocks 13. Safe mode will be turned off automatically.
         at
org.apache.hadoop.hdfs.server.namenode.FSNamesystem.mkdirsInternal(FSNamesystem.java:1966)
         at
org.apache.hadoop.hdfs.server.namenode.FSNamesystem.mkdirs(FSNamesystem.java:1940)
         at
org.apache.hadoop.hdfs.server.namenode.NameNode.mkdirs(NameNode.java:770)
         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)
Some staging files seem to have been created however.

I was thinking of sending this to the mahout mailing list but it seems a
more core hadoop issue.

We are using the following command to launch the mahout example:
./mahout org.apache.mahout.clustering.syntheticcontrol.kmeans.Job
--input hdfs://master/user/hdfs/testdata/synthetic_control.data --output
hdfs://master/user/hdfs/testdata/output --t1 0.5 --t2 1 --maxIter 50

Any clues?
George

--

---------------------------

George Kousiouris
Electrical and Computer Engineer
Division of Communications,
Electronics and Information Engineering
School of Electrical and Computer Engineering
Tel: +30 210 772 2546
Mobile: +30 6939354121
Fax: +30 210 772 2569
Email: [EMAIL PROTECTED]
Site: http://users.ntua.gr/gkousiou/

National Technical University of Athens
9 Heroon Polytechniou str., 157 73 Zografou, Athens, Greece