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Vinod K V commented on MAPREDUCE-1266: -------------------------------------- bq. BTW, the inspiration was this blog post: http://pero.blogs.aprilmayjune.org/2009/11/30/improve-performance-on-small-hadoop-clusters/ Just a thought, is this improvement perceivable at full/heavy job-load? Heart-beats in an idle cluster are mostly very cheap. Heavy load involves costlier heartbeat processing and so may or may not show the performance improvements you have outlined.. > Allow heartbeat interval smaller than 3 seconds for tiny clusters > ----------------------------------------------------------------- > > Key: MAPREDUCE-1266 > URL: https://issues.apache.org/jira/browse/MAPREDUCE-1266 > Project: Hadoop Map/Reduce > Issue Type: Improvement > Components: jobtracker, task, tasktracker > Affects Versions: 0.22.0 > Reporter: Todd Lipcon > Priority: Minor > > For small clusters, the heartbeat interval has a large effect on job latency. > This is especially true on pseudo-distributed or other "tiny" (<5 nodes) > clusters. It's not a big deal for production, but new users would have a > happier first experience if Hadoop seemed snappier. > I'd like to change the minimum heartbeat interval from 3.0 seconds to perhaps > 0.5 seconds (but have it governed by an undocumented config parameter in case > people don't like this change). The cluster size-based ramp up of interval > will maintain the current scalable behavior for large clusters with no > negative effect. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.