[ 
https://issues.apache.org/jira/browse/HDFS-4739?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13641155#comment-13641155
 ] 

Aaron T. Myers commented on HDFS-4739:
--------------------------------------

Thanks a lot for the reviews, Todd and Chris. I'm fairly confident that the 
test failure is unrelated - that test has been failing intermittently pretty 
frequently lately.

I'm going to commit this momentarily.
                
> NN can miscalculate the number of extra edit log segments to retain
> -------------------------------------------------------------------
>
>                 Key: HDFS-4739
>                 URL: https://issues.apache.org/jira/browse/HDFS-4739
>             Project: Hadoop HDFS
>          Issue Type: Bug
>          Components: namenode
>    Affects Versions: 2.0.4-alpha
>            Reporter: Aaron T. Myers
>            Assignee: Aaron T. Myers
>         Attachments: HDFS-4739.patch, HDFS-4739.patch
>
>
> The code in NNStorageRetentionManager#purgeOldStorage is intended to place a 
> cap on the number of _extra_ edit log segments retained beyond what is 
> strictly required to replay the FS history since the last fsimage. In fact 
> this code currently places a limit on the _total_ number of extra edit log 
> segments. If the number of required segments is greater than the configured 
> cap, there will be no data loss, but an ugly error will be thrown and the NN 
> will fail to start.
> The fix is simple, and in the meantime a work-around is just to raise the 
> value of dfs.namenode.max.extra.edits.segments.retained and start the NN.

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira

Reply via email to