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Posted to hdfs-dev@hadoop.apache.org by "Ming Ma (JIRA)" <ji...@apache.org> on 2013/12/21 00:38:09 UTC

[jira] [Created] (HDFS-5693) Few NN metrics data points were collected via JMX when NN is under heavy load

Ming Ma created HDFS-5693:
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             Summary: Few NN metrics data points were collected via JMX when NN is under heavy load
                 Key: HDFS-5693
                 URL: https://issues.apache.org/jira/browse/HDFS-5693
             Project: Hadoop HDFS
          Issue Type: Improvement
          Components: namenode
            Reporter: Ming Ma




JMX sometimes doesn’t return any value when NN is under heavy load. However, that is when we would like to get metrics to help to diagnosis the issue.

When NN is under heavy load due to bad application or other reasons, it holds FSNamesystem's writer lock for a long period of time. Many of the FSNamesystem metrics require FSNamesystem's reader lock and thus can't be processed.

This is a special case to improve the overall NN concurrency.



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