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https://issues.apache.org/jira/browse/AMBARI-24244?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Hari Sekhon updated AMBARI-24244:
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Summary: Grafana HBase GC Time graph showing very wrong GC times (off by
many secs) (was: Ambari)
> Grafana HBase GC Time graph showing very wrong GC times (off by many secs)
> --------------------------------------------------------------------------
>
> Key: AMBARI-24244
> URL: https://issues.apache.org/jira/browse/AMBARI-24244
> Project: Ambari
> Issue Type: Bug
> Components: ambari-metrics, metrics
> Affects Versions: 2.5.2
> Reporter: Hari Sekhon
> Priority: Major
>
> Ambari's in-built Grafana graph for "JVM GC Times" graph in the HBase -
> RegionServers dashboard is very wrong and doesn't reflect the times I've
> grepped across HBase RegionServer logs for util.JvmPauseMonitor.
> I've inherited a very heavily loaded HBase + OpenTSDB cluster where there are
> RegionServer losses occurring due to GCs around 30 seconds(!) causing ZK +
> HMaster to declare them dead. The Grafana graphs show peaks around 70ms due
> to avg downsampling. Editing the graph and changing Aggregator from 'avg' to
> 'none' and Transform from 'rate' to 'diff' seems to brings the graph closer
> to what the actual logs and behaviour are showing. But this might need more
> fiddling and investigation.
> Right now the GC Times graph which is incredibly important is worse than
> useless, it's misleading as it shows there are no GC issues when there are
> actually very large very severe GC issues on this cluster.
> This is a vanilla Ambari deployed Grafana with Ambari Metrics.
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