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Posted to common-dev@hadoop.apache.org by "Amar Kamat (JIRA)" <ji...@apache.org> on 2009/03/03 05:02:56 UTC
[jira] Resolved: (HADOOP-5377) Inefficient jobtracker history file
layout
[ https://issues.apache.org/jira/browse/HADOOP-5377?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Amar Kamat resolved HADOOP-5377.
--------------------------------
Resolution: Duplicate
Nick, HADOOP-4670 is opened to address the same.
> Inefficient jobtracker history file layout
> ------------------------------------------
>
> Key: HADOOP-5377
> URL: https://issues.apache.org/jira/browse/HADOOP-5377
> Project: Hadoop Core
> Issue Type: Bug
> Components: mapred
> Environment: This is at least a problem on 0.15.
> Reporter: Nick Rettinghouse
>
> Storing too many files in a single directory slows things down tremendously and in this case, makes the grid just a bit more difficult to manage. On our jobtrackers, even with a 45 day purge cycle, we see hundreds of thousands of files in logs/hadoop/history. The following is an example:
> pchdm01.ypost.re1: logs/hadoop/history - 1,176,927 files!
> This is the time(1) output of the `ls | wc -l`
> real 0m56.042s
> user 0m28.702s
> sys 0m1.794s
> Note that this was the second time I ran this filecount. The first run took more than 4 minutes of real time.
> ===========================================
> My recommended solution is that the Hadoop team store these files in the following structure:
> history/2008/08/19
> history/2008/08/20
> history/2008/08/21
> Using this structure gives us 2 important things: consistently good performance and the ability to easily delete or archive old files.
> If we expect a Hadoop cluster to process hundreds of thousands of jobs per day, then we may want to break it down by
> hour like this:
> history/2008/08/19/00
> history/2008/08/19/01
> ...
> history/2008/08/19/22
> history/2008/08/19/23
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