hadoop-hdfs-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "dhruba borthakur (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HDFS-1982) Null pointer exception is thrown when NN restarts with a block lesser in size than the block that is present in DN1 but the generation stamp is greater in the NN
Date Mon, 30 May 2011 19:05:47 GMT

    [ https://issues.apache.org/jira/browse/HDFS-1982?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13041236#comment-13041236
] 

dhruba borthakur commented on HDFS-1982:
----------------------------------------

Theoretically, this seems plausible. are you experiencing it? do u have a unit test that I
can use to reliably reproduce this problem?

> Null pointer exception is thrown when NN restarts with a block lesser in size than the
block that is present in DN1 but the generation stamp is greater in the NN 
> ------------------------------------------------------------------------------------------------------------------------------------------------------------------
>
>                 Key: HDFS-1982
>                 URL: https://issues.apache.org/jira/browse/HDFS-1982
>             Project: Hadoop HDFS
>          Issue Type: Bug
>          Components: name-node
>    Affects Versions: 0.20-append
>         Environment: Linux
>            Reporter: ramkrishna.s.vasudevan
>             Fix For: 0.20-append
>
>
> Conisder the following scenario. 
> WE have a cluster with one NN and 2 DN.
> We write some file.
> One of the block is written in DN1 but not yet completed in DN2 local disk.
> Now DN1 gets killed and so pipeline recovery happens for the block with the size as in
DN2 but the generation stamp gets updated in the NN.
> DN2 also gets killed.
> Now restart NN and DN1
> Now if NN restarts, the block that NN has greater time stamp but the size is lesser in
the NN.
> This leads to Null pointer exception in addstoredblock api

--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira

Mime
View raw message