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https://issues.apache.org/jira/browse/HDFS-3415?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13278409#comment-13278409
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Brandon Li commented on HDFS-3415:
----------------------------------
I reproduce this problem with the following configuration:
1. set two storage directories, say dirA and dirB
2. start and then shutdown namenode
3. change only dirB's layout version from -40 to 123.
4. start namenode and it should fail with the above NullPointerException
The problem here is:
Two storage inspectors are used in namenode,
FSImagePreTransactionalStorageInspector for layout version before -38, and
FSImageTransactionalStorageInspector for -38 or anything later.
In this case, the modified storage directory happens to be the last one
inspected by the namenode in order to load image/edits. Even though it sees two
layout version, it saves the last one ("123" in this case) as the storage
layout version. However, it uses FSImageTransactionalStorageInspector to get
image path because dirA still has -40 and then uses
FSImagePreTransactionalStorageInspector to get edit stream. Because
FSImagePreTransactionalStorageInspector can't recognize
the file in a storage directory whose real version is newer, some references
are not initialized which eventually cause the exception.
> NameNode is getting shutdown by throwing nullpointer exception when one of
> the layout version is different with others(Multiple storage dirs are
> configured)
> ------------------------------------------------------------------------------------------------------------------------------------------------------------
>
> Key: HDFS-3415
> URL: https://issues.apache.org/jira/browse/HDFS-3415
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: name-node
> Affects Versions: 2.0.0, 3.0.0
> Environment: Suse linux + jdk 1.6
> Reporter: Brahma Reddy Battula
> Assignee: Brandon Li
>
> Scenario:
> =========
> start Namenode and datanode by configuring three storage dir's for namenode
> write 10 files
> edit version file of one of the storage dir and give layout version as 123
> which different with default(-40).
> Stop namenode
> start Namenode.
> Then I am getting follwong exception...
> {noformat}
> 2012-05-13 19:01:41,483 ERROR
> org.apache.hadoop.hdfs.server.namenode.NameNode: Exception in namenode join
> java.lang.NullPointerException
> at
> org.apache.hadoop.hdfs.server.namenode.NNStorage.getStorageFile(NNStorage.java:686)
> at
> org.apache.hadoop.hdfs.server.namenode.FSImagePreTransactionalStorageInspector.getEditsInStorageDir(FSImagePreTransactionalStorageInspector.java:243)
> at
> org.apache.hadoop.hdfs.server.namenode.FSImagePreTransactionalStorageInspector.getLatestEditsFiles(FSImagePreTransactionalStorageInspector.java:261)
> at
> org.apache.hadoop.hdfs.server.namenode.FSImagePreTransactionalStorageInspector.getEditLogStreams(FSImagePreTransactionalStorageInspector.java:276)
> at
> org.apache.hadoop.hdfs.server.namenode.FSImage.loadFSImage(FSImage.java:596)
> at
> org.apache.hadoop.hdfs.server.namenode.FSImage.recoverTransitionRead(FSImage.java:247)
> at
> org.apache.hadoop.hdfs.server.namenode.FSNamesystem.loadFSImage(FSNamesystem.java:498)
> at
> org.apache.hadoop.hdfs.server.namenode.FSNamesystem.loadFromDisk(FSNamesystem.java:390)
> at
> org.apache.hadoop.hdfs.server.namenode.FSNamesystem.loadFromDisk(FSNamesystem.java:354)
> at
> org.apache.hadoop.hdfs.server.namenode.NameNode.loadNamesystem(NameNode.java:368)
> at
> org.apache.hadoop.hdfs.server.namenode.NameNode.initialize(NameNode.java:402)
> at
> org.apache.hadoop.hdfs.server.namenode.NameNode.<init>(NameNode.java:564)
> at
> org.apache.hadoop.hdfs.server.namenode.NameNode.<init>(NameNode.java:545)
> at
> org.apache.hadoop.hdfs.server.namenode.NameNode.createNameNode(NameNode.java:1093)
> at
> org.apache.hadoop.hdfs.server.namenode.NameNode.main(NameNode.java:1151)
> 2012-05-13 19:01:41,485 INFO org.apache.hadoop.hdfs.server.namenode.NameNode:
> SHUTDOWN_MSG:
> {noformat}
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