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https://issues.apache.org/jira/browse/HDFS-7609?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14527030#comment-14527030
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Ming Ma commented on HDFS-7609:
-------------------------------
#3 in the scenario description above should be "Before nn2 starts the
transition to active" instead of "Even though nn2 is still tailing edit log
and not active yet", because after nn2 starts tailing edit log, it will lock
retryCache until it becomes active and thus prevent the client calls from
adding new entry to the retry cache during the transition.
> startup used too much time to load edits
> ----------------------------------------
>
> Key: HDFS-7609
> URL: https://issues.apache.org/jira/browse/HDFS-7609
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: namenode
> Affects Versions: 2.2.0
> Reporter: Carrey Zhan
> Assignee: Ming Ma
> Attachments: HDFS-7609-CreateEditsLogWithRPCIDs.patch,
> HDFS-7609.patch, recovery_do_not_use_retrycache.patch
>
>
> One day my namenode crashed because of two journal node timed out at the same
> time under very high load, leaving behind about 100 million transactions in
> edits log.(I still have no idea why they were not rolled into fsimage.)
> I tryed to restart namenode, but it showed that almost 20 hours would be
> needed before finish, and it was loading fsedits most of the time. I also
> tryed to restart namenode in recover mode, the loading speed had no different.
> I looked into the stack trace, judged that it is caused by the retry cache.
> So I set dfs.namenode.enable.retrycache to false, the restart process
> finished in half an hour.
> I think the retry cached is useless during startup, at least during recover
> process.
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