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Jeremy Hanna commented on CASSANDRA-15839: ------------------------------------------ This is the code that *should* detect whether or not G1 is enabled. However since you can either enable or disable it with that string {{+UseG1GC}} or {{-UseG1GC}}. I have to admit I've never seen anyone in practice explicitly disable G1. {code:sh} echo $JVM_OPTS | grep -q UseG1GC USING_G1=$? {code} That also affects whether we calculate heap sizes automatically or whether we fail out when we don't set the heap and new size in pairs: {code:sh} # only calculate the size if it's not set manually if [ "x$MAX_HEAP_SIZE" = "x" ] && [ "x$HEAP_NEWSIZE" = "x" -o $USING_G1 -eq 0 ]; then calculate_heap_sizes elif [ "x$MAX_HEAP_SIZE" = "x" ] || [ "x$HEAP_NEWSIZE" = "x" -a $USING_G1 -ne 0 ]; then echo "please set or unset MAX_HEAP_SIZE and HEAP_NEWSIZE in pairs when using CMS GC (see cassandra-env.sh)" exit 1 fi {code} Created CASSANDRA-15931 to address this. > Warn or fail to start server when G1 is used and Xmn is set > ----------------------------------------------------------- > > Key: CASSANDRA-15839 > URL: https://issues.apache.org/jira/browse/CASSANDRA-15839 > Project: Cassandra > Issue Type: Improvement > Components: Local/Startup and Shutdown > Reporter: Jeremy Hanna > Assignee: Anthony Grasso > Priority: Normal > Fix For: 4.0, 4.0-alpha5 > > > In jvm.options, we currently have a comment above where Xmn is set that says > that you shouldn't set Xmn with G1 GC. That isn't enough - we should either > warn in the logs or fail startup when they are set together. -- This message was sent by Atlassian Jira (v8.3.4#803005) --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@cassandra.apache.org For additional commands, e-mail: commits-h...@cassandra.apache.org