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Oleg Anastasyev commented on CASSANDRA-8150: -------------------------------------------- Let me add 2 -cents- GC options from our production clusters, which i believe could be useful for all: -XX:+CMSScavengeBeforeRemark to reduce rescan phase even of CMSWait exceeded -XX:+ParallelRefProcEnabled -XX:+CMSParallelInitialMarkEnabled to improve CMS parallelization -XX:CMSMaxAbortablePrecleanTime=20000 I'd also propose add -XX:+DisableExplicitGC , b/c java RMI runtime invokes a System.gc every hour or increasing sun.rmi.dgc.server.gcInterval to infinity. We found, that on Sun JVMs 7 and 8 CMSWait durations are not governed by CMS when GC is initiated by System.gc and this was the reason for most long rescan phase pauses. > Revaluate Default JVM tuning parameters > --------------------------------------- > > Key: CASSANDRA-8150 > URL: https://issues.apache.org/jira/browse/CASSANDRA-8150 > Project: Cassandra > Issue Type: Improvement > Components: Config > Reporter: Matt Stump > Assignee: Brandon Williams > Attachments: upload.png > > > It's been found that the old twitter recommendations of 100m per core up to > 800m is harmful and should no longer be used. > Instead the formula used should be 1/3 or 1/4 max heap with a max of 2G. 1/3 > or 1/4 is debatable and I'm open to suggestions. If I were to hazard a guess > 1/3 is probably better for releases greater than 2.1. -- This message was sent by Atlassian JIRA (v6.3.4#6332)