[HADOOP-2647] dfs -put hangs

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.15.1
• Fix Version/s: 0.15.4

Environment

LINUX

• Assignee: Raghu Angadi
• Reporter: Lohit Vijaya Renu
• Created: 17/Jan/08 22:25
• Updated: 08/Jul/09 16:42
• Resolved: 19/Feb/08 20:41

Description

We saw a case where dfs -put hung while copying a 2GB file for over 20 hours.
When we took a look at the stack trace of process the main thread was waiting for confirmation from namenode for complete status.
only 4 blocks were copied and 5th block was missing when we ran fsck on the partially transfered file.

There are 2 problems we saw here.

1. DFS client hung without a timeout when there is no response from namenode.
2. In IOUtils::copyBytes(InputStream in, OutputStream out, int buffSize, boolean close)
During copy, if there is an exception, the out.close() is called. Exception is not caught. Which is why we see a close call in the stack trace.

When we checked for block IDs in namenode log. For the block which was missing, there was only one response to namenode instead of three.
This close state coupled with namenode not reporting the error back might have cause the whole process to hang.

Opening this JIRA to see if we could add checks to the two problems mentioned above.

<stack trace of main thread>
"main" prio=10 tid=0x0805a000 nid=0x5b53 waiting on condition [0xf7e64000..0xf7e65288] java.lang.Thread.State: TIMED_WAITING (sleeping)
at java.lang.Thread.sleep(Native Method)
at org.apache.hadoop.dfs.DFSClient$DFSOutputStream.close(DFSClient.java:1751) - locked <0x77d593a0> (a org.apache.hadoop.dfs.DFSClient$DFSOutputStream) at org.apache.hadoop.fs.FSDataOutputStream$PositionCache.close(FSDataOutputStream.java:49)
at org.apache.hadoop.fs.FSDataOutputStream.close(FSDataOutputStream.java:64) at org.apache.hadoop.io.IOUtils.copyBytes(IOUtils.java:55)
at org.apache.hadoop.io.IOUtils.copyBytes(IOUtils.java:83) at org.apache.hadoop.fs.FileUtil.copy(FileUtil.java:140)
at org.apache.hadoop.fs.FileSystem.copyFromLocalFile(FileSystem.java:826)
at org.apache.hadoop.fs.FsShell.copyFromLocal(FsShell.java:114)
at org.apache.hadoop.fs.FsShell.run(FsShell.java:1354)
at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:65) at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:79)
at org.apache.hadoop.fs.FsShell.main(FsShell.java:1472)
</stack trace of main thread>

Issue Links

• relates to: HDFS-350 DFSClient more robust if the namenode is busy doing GC