After upgrading to hadoop-0.20.2, I started seeing these messages in the log:
2010-03-22 09:56:28,393 INFO org.apache.hadoop.ipc.Server: IPC Server handler 1 on 9000, call addBlock(/home/training/hadoop/mapred/system/ jobtracker.info, DFSClient_-1956918169) from 127.0.0.1:41067: error: java.io.IOException: File /home/training/hadoop/mapred/system/ jobtracker.info could only be replicated to 0 nodes, instead of 1 java.io.IOException: File /home/training/hadoop/mapred/system/ jobtracker.info could only be replicated to 0 nodes, instead of 1 at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.getAdditionalBlock(FSNamesystem.java:1271) at org.apache.hadoop.hdfs.server.namenode.NameNode.addBlock(NameNode.java:422) 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.ipc.RPC$Server.call(RPC.java:508) at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:959) at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:955) at java.security.AccessController.doPrivileged(Native Method) at javax.security.auth.Subject.doAs(Subject.java:396) at org.apache.hadoop.ipc.Server$Handler.run(Server.java:953) I am running in Psuedo-distributed mode. Before upgrading I used to see these messages occasionally, but they were harmless. Now I see these when I try to copy files to DFS using -copyFromLocal, and the files no longer get copied :( I mean, it's quite possible, this has nothing to do with the Hadoop upgrade but something changed in my environment, but any help will be appreciated. Thanks.