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From "Ming Ma (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HDFS-7609) startup used too much time to load edits
Date Tue, 27 Jan 2015 00:13:35 GMT

    [ https://issues.apache.org/jira/browse/HDFS-7609?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14292690#comment-14292690
] 

Ming Ma commented on HDFS-7609:
-------------------------------

[~cnauroth], we upgraded from hadoop 2.0.5 to hadoop 2.4, so yes, from a version without this
feature to the version with the feature. Last time during investigation via code review, it
appears {{toAddRetryCache}} should be set to false if standby replays old edit logs generated
by hadoop version without retrycache.

{noformat}
      if (toAddRetryCache) {
        fsNamesys.addCacheEntry(deleteOp.rpcClientId, deleteOp.rpcCallId);
      }
{noformat}

> 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
>         Attachments: HDFS-7609-CreateEditsLogWithRPCIDs.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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