| ########################################################################### |
| # jvm8-server.options # |
| # # |
| # See jvm-server.options. This file is specific for Java 8 and newer. # |
| ########################################################################### |
| |
| ######################## |
| # GENERAL JVM SETTINGS # |
| ######################## |
| |
| # allows lowering thread priority without being root on linux - probably |
| # not necessary on Windows but doesn't harm anything. |
| # see http://tech.stolsvik.com/2010/01/linux-java-thread-priorities-workaround.html |
| -XX:ThreadPriorityPolicy=42 |
| |
| ################# |
| # GC SETTINGS # |
| ################# |
| |
| ### CMS Settings |
| -XX:+UseParNewGC |
| -XX:+UseConcMarkSweepGC |
| -XX:+CMSParallelRemarkEnabled |
| -XX:SurvivorRatio=8 |
| -XX:MaxTenuringThreshold=1 |
| -XX:CMSInitiatingOccupancyFraction=75 |
| -XX:+UseCMSInitiatingOccupancyOnly |
| -XX:CMSWaitDuration=10000 |
| -XX:+CMSParallelInitialMarkEnabled |
| -XX:+CMSEdenChunksRecordAlways |
| ## some JVMs will fill up their heap when accessed via JMX, see CASSANDRA-6541 |
| -XX:+CMSClassUnloadingEnabled |
| |
| ### G1 Settings |
| ## Use the Hotspot garbage-first collector. |
| #-XX:+UseG1GC |
| #-XX:+ParallelRefProcEnabled |
| |
| # |
| ## Have the JVM do less remembered set work during STW, instead |
| ## preferring concurrent GC. Reduces p99.9 latency. |
| #-XX:G1RSetUpdatingPauseTimePercent=5 |
| # |
| ## Main G1GC tunable: lowering the pause target will lower throughput and vise versa. |
| ## 200ms is the JVM default and lowest viable setting |
| ## 1000ms increases throughput. Keep it smaller than the timeouts in cassandra.yaml. |
| #-XX:MaxGCPauseMillis=500 |
| |
| ## Optional G1 Settings |
| # Save CPU time on large (>= 16GB) heaps by delaying region scanning |
| # until the heap is 70% full. The default in Hotspot 8u40 is 40%. |
| #-XX:InitiatingHeapOccupancyPercent=70 |
| |
| # For systems with > 8 cores, the default ParallelGCThreads is 5/8 the number of logical cores. |
| # Otherwise equal to the number of cores when 8 or less. |
| # Machines with > 10 cores should try setting these to <= full cores. |
| #-XX:ParallelGCThreads=16 |
| # By default, ConcGCThreads is 1/4 of ParallelGCThreads. |
| # Setting both to the same value can reduce STW durations. |
| #-XX:ConcGCThreads=16 |
| |
| ### GC logging options -- uncomment to enable |
| |
| -XX:+PrintGCDetails |
| -XX:+PrintGCDateStamps |
| -XX:+PrintHeapAtGC |
| -XX:+PrintTenuringDistribution |
| -XX:+PrintGCApplicationStoppedTime |
| -XX:+PrintPromotionFailure |
| #-XX:PrintFLSStatistics=1 |
| #-Xloggc:/var/log/cassandra/gc.log |
| -XX:+UseGCLogFileRotation |
| -XX:NumberOfGCLogFiles=10 |
| -XX:GCLogFileSize=10M |
| |
| # The newline in the end of file is intentional |
