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https://issues.apache.org/jira/browse/HADOOP-2050?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12534570
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Runping Qi commented on HADOOP-2050:
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This problem does not happen if the dfs write load is low.
When a few mappers copy files, the problem did not show up.
Only when the number of mappers reach beyond 50 (the dfs cluster has about 400
nodes), the
problem happened consistently.
> distcp failed due to problem in creating files
> ----------------------------------------------
>
> Key: HADOOP-2050
> URL: https://issues.apache.org/jira/browse/HADOOP-2050
> Project: Hadoop
> Issue Type: Bug
> Components: dfs
> Affects Versions: 0.15.0
> Reporter: Runping Qi
>
> When I run a distcp program to copy files from one dfs to another, my job
> failed with
> the mappers throwing the following exception:
> org.apache.hadoop.ipc.RemoteException:
> org.apache.hadoop.dfs.AlreadyBeingCreatedException: failed to create file
> /xxxxx/part-00007 for DFSClient_task_200710122302_0002_m_000456_2 on client
> 72.30.43.23 because current leaseholder is trying to recreate file.
> at
> org.apache.hadoop.dfs.FSNamesystem.startFileInternal(FSNamesystem.java:850)
> at org.apache.hadoop.dfs.FSNamesystem.startFile(FSNamesystem.java:806)
> at org.apache.hadoop.dfs.NameNode.create(NameNode.java:333)
> at sun.reflect.GeneratedMethodAccessor13.invoke(Unknown Source)
> at
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
> at java.lang.reflect.Method.invoke(Method.java:597)
> at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:379)
> at org.apache.hadoop.ipc.Server$Handler.run(Server.java:596)
> at org.apache.hadoop.ipc.Client.call(Client.java:482)
> at org.apache.hadoop.ipc.RPC$Invoker.invoke(RPC.java:184)
> at org.apache.hadoop.dfs.$Proxy1.create(Unknown Source)
> 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.io.retry.RetryInvocationHandler.invokeMethod(RetryInvocationHandler.java:82)
> at
> org.apache.hadoop.io.retry.RetryInvocationHandler.invoke(RetryInvocationHandler.java:59)
> at org.apache.hadoop.dfs.$Proxy1.create(Unknown Source)
> at org.apache.hadoop.dfs.DFSClient$DFSOutputStream.(DFSClient.java:1432)
> at org.apache.hadoop.dfs.DFSClient.create(DFSClient.java:376)
> at
> org.apache.hadoop.dfs.DistributedFileSystem.create(DistributedFileSystem.java:121)
> at
> org.apache.hadoop.util.CopyFiles$FSCopyFilesMapper.copy(CopyFiles.java:284)
> at
> org.apache.hadoop.util.CopyFiles$FSCopyFilesMapper.map(CopyFiles.java:352)
> at
> org.apache.hadoop.util.CopyFiles$FSCopyFilesMapper.map(CopyFiles.java:217)
> at org.apache.hadoop.mapred.MapRunner.run(MapRunner.java:50)
> at org.apache.hadoop.mapred.MapTask.run(MapTask.java:195)
> at
> org.apache.hadoop.mapred.TaskTracker$Child.main(TaskTracker.java:1750)
> It seems that this problem happened in the 2nd, 3rd, 4th attempts,
> after the first attemp failed.
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