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https://issues.apache.org/jira/browse/HADOOP-1076?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12530243
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Hudson commented on HADOOP-1076:
--------------------------------
Integrated in Hadoop-Nightly #250 (See
[http://lucene.zones.apache.org:8080/hudson/job/Hadoop-Nightly/250/])
> Periodic checkpointing cannot resume if the secondary name-node fails.
> ----------------------------------------------------------------------
>
> Key: HADOOP-1076
> URL: https://issues.apache.org/jira/browse/HADOOP-1076
> Project: Hadoop
> Issue Type: Bug
> Components: dfs
> Reporter: Konstantin Shvachko
> Assignee: dhruba borthakur
> Fix For: 0.15.0
>
> Attachments: secondaryRestart4.patch
>
>
> If secondary name-node fails during checkpointing then the primary node will
> have 2 edits file.
> "edits" - is the one which current checkpoint is to be based upon.
> "edits.new" - is where new name space edits are currently logged.
> The problem is that the primary node cannot do checkpointing until
> "edits.new" file is in place.
> That is, even if the secondary name-node is restarted periodic checkpointing
> is not going to be resumed.
> In fact the primary node will be throwing an exception complaining about the
> existing "edits.new"
> There is only one way to get rid of the edits.new file - to restart the
> primary name-node.
> So in a way if secondary name-node fails then you should restart the whole
> cluster.
> Here is a rather simple modification to the current approach, which we
> discussed with Dhruba.
> When secondary node requests to rollEditLog() the primary node should roll
> the edit log only if
> it has not been already rolled. Otherwise the existing "edits" file will be
> used for checkpointing
> and the primary node will keep accumulating new edits in the "edits.new".
> In order to make it work the primary node should also ignore any
> rollFSImage() requests when it
> already started to perform one. Otherwise the new image can become corrupted
> if two secondary
> nodes request to rollFSImage() at the same time.
> 2. Also, after the periodic checkpointing patch HADOOP-227 I see pieces of
> unusable code.
> I noticed one data member SecondaryNameNode.localName and at least 4 methods
> in FSEditLog
> that are not used anywhere. We should remove them and others alike if found.
> Supporting unusable code is such a waist of time.
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