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https://issues.apache.org/jira/browse/HDFS-4486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14097308#comment-14097308
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Zhe Zhang commented on HDFS-4486:
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[~tlipcon] I wonder if you can share a little more details on the short circuit
read and native checksumming use cases. What particular metrics are of interest
(e.g. IOPS)? Depending on that, it might make sense to make it a JMX metric
instead of free text logging.
> Add log category for long-running DFSClient notices
> ---------------------------------------------------
>
> Key: HDFS-4486
> URL: https://issues.apache.org/jira/browse/HDFS-4486
> Project: Hadoop HDFS
> Issue Type: Improvement
> Reporter: Todd Lipcon
> Assignee: Zhe Zhang
> Priority: Minor
>
> There are a number of features in the DFS client which are transparent but
> can make a fairly big difference for performance -- two in particular are
> short circuit reads and native checksumming. Because we don't want log spew
> for clients like "hadoop fs -cat" we currently log only at DEBUG level when
> these features are disabled. This makes it difficult to troubleshoot/verify
> for long-running perf-sensitive clients like HBase.
> One simple solution is to add a new log category - eg
> o.a.h.h.DFSClient.PerformanceAdvisory - which long-running clients could
> enable at DEBUG level without getting the full debug spew.
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