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https://issues.apache.org/jira/browse/HDFS-4183?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13496594#comment-13496594
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Tsz Wo (Nicholas), SZE commented on HDFS-4183:
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This problem looks very similar to the large delete problem: the LeaseManager
recovers all expired leases at the same time. We could limit the number of
leases in each iteration and then we are done since the thread sleeps for
NAMENODE_LEASE_RECHECK_INTERVAL between iterations.
> ... I propose configurable rate with 300/min as default.
I think it is too small but I don't have experimental data to support my
argument.
> Throttle block recovery
> -----------------------
>
> Key: HDFS-4183
> URL: https://issues.apache.org/jira/browse/HDFS-4183
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: name-node
> Affects Versions: 0.23.4, 2.0.2-alpha
> Reporter: Kihwal Lee
> Assignee: Kihwal Lee
> Priority: Critical
>
> When a large number of files are abandoned without closing, a storm of lease
> expiration follows in about an hour (lease hard limit). For the last block of
> each file, block recovery is initiated and when the datanode is done, it
> calls commitBlockSynchronization() is called against namenode. A burst of
> these calls can slow down namenode considerably. We need to throttle block
> recovery and/or speed up the rate at which commitBlockSynchronization() is
> served.
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