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https://issues.apache.org/jira/browse/HADOOP-1188?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12563911#action_12563911
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dhruba borthakur commented on HADOOP-1188:
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I am still reviewing this patch, but two preliminary comments:
1. If a directory becomes bad, then we increment the timestamp and write the
new timestamp into all remaining good directories. If the write of this new
timestamp to a good directory fails, then we *again* increment the timestamp
and then write this new timestamp to *all* known good directories.
2. This is very crucial piece of namenode code. It would be nice to have a unit
test.
> processIOError() should update fstime file
> ------------------------------------------
>
> Key: HADOOP-1188
> URL: https://issues.apache.org/jira/browse/HADOOP-1188
> Project: Hadoop Core
> Issue Type: Bug
> Components: dfs
> Affects Versions: 0.10.1, 0.11.2, 0.12.2
> Reporter: Konstantin Shvachko
> Assignee: Konstantin Shvachko
> Priority: Blocker
> Fix For: 0.16.1
>
> Attachments: hadoop-1188.patch
>
>
> Name-node can have multiple directories to store the name space image and
> edits.
> During startup the name-node selects the latest image and reads it in memory.
> fstime stores the time of the latest checkpoint.
> If one of the directories becomes inaccessible during normal operation the
> name-node
> excludes it from the list, and never writes anything into it until restarted.
> Now if the the name-node restarts after excluding one of the directories, and
> if that
> excluded directory contained the latest image, then all modifications of the
> name space
> recorded in edits files in other directories starting from the moment the
> directory was
> excluded will be lost.
> We should update fstime in all remaining good directories after the exclusion.
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