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https://issues.apache.org/jira/browse/MAPREDUCE-1906?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Scott Carey updated MAPREDUCE-1906:
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Attachment: MAPREDUCE-1906-0.21.patch
This patch changes the default minimum TaskTracker > JobTracker heartbeat
interval from 3000ms to 300ms.
Effectively, this makes clusters between 30 and 300 nodes increase their
heartbeat rate to a cluster-wide 100 heartbeats per second.
Clusters larger than 300 nodes remain unchanged at a cluster-wide 100
heartbeats per second.
Clusters with less than 30 nodes have a constant 300ms between pings per node.
so for a 15 node cluster it is 50 heartbeats per second, and for a 3 node
cluster it is 10 heartbeats per second.
> Lower minimum heartbeat interval for tasktracker > Jobtracker
> -------------------------------------------------------------
>
> Key: MAPREDUCE-1906
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-1906
> Project: Hadoop Map/Reduce
> Issue Type: Improvement
> Affects Versions: 0.20.1, 0.20.2
> Reporter: Scott Carey
> Attachments: MAPREDUCE-1906-0.21.patch
>
>
> I get a 0% to 15% performance increase for smaller clusters by making the
> heartbeat throttle stop penalizing clusters with less than 300 nodes.
> Between 0.19 and 0.20, the default minimum heartbeat interval increased from
> 2s to 3s. If a JobTracker is throttled at 100 heartbeats / sec for large
> clusters, why should a cluster with 10 nodes be throttled to 3.3 heartbeats
> per second?
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