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https://issues.apache.org/jira/browse/HDFS-1348?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Hairong Kuang updated HDFS-1348:
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Summary: Improve NameNode reponsiveness while it is checking if
datanode decommissions are complete (was: DecommissionManager holds
fsnamesystem lock during the whole process of checking if decomissioning
DataNodes are finished or not)
Description:
NameNode normally is busy all the time. Its log is full of activities every
second. But once for a while, NameNode seems to pause for more than 10 seconds
without doing anything, leaving a blank in its log even though no garbage
collection is happening. All other requests to NameNode are blocked when this
is happening.
One culprit is DecommionManager. Its monitor holds the fsynamesystem lock
during the whole process of checking if decomissioning DataNodes are finished
or not, during which it checks every block of up to a default of 5 datanodes.
was:
NameNode normally is busy all the time. Its log is full of activities every
second. But once for a while, NameNode seems to pause for more than 10 seconds
without doing anything, leaving a blank in its log even though no garbage
collection is happening.
One culprit is DecommionManager. Its monitor holds the fsynamesystem lock
during the whole process of checking if decomissioning DataNodes are finished
or not, during which it checks every block of up to a default of 5 datanodes.
> Improve NameNode reponsiveness while it is checking if datanode decommissions
> are complete
> ------------------------------------------------------------------------------------------
>
> Key: HDFS-1348
> URL: https://issues.apache.org/jira/browse/HDFS-1348
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: name-node
> Reporter: Hairong Kuang
> Assignee: Hairong Kuang
> Fix For: 0.22.0
>
>
> NameNode normally is busy all the time. Its log is full of activities every
> second. But once for a while, NameNode seems to pause for more than 10
> seconds without doing anything, leaving a blank in its log even though no
> garbage collection is happening. All other requests to NameNode are blocked
> when this is happening.
> One culprit is DecommionManager. Its monitor holds the fsynamesystem lock
> during the whole process of checking if decomissioning DataNodes are finished
> or not, during which it checks every block of up to a default of 5 datanodes.
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