When I started my Cassandra cluster with version 3.11.6 the available memory was 15% and after 4,5 day it comes down to 10 % and gradually decreasing, do we need to change some setting there so that available memory is always remain constant around 14 to 15% . When I was running Cassandra cluster with version 2.2.8, the available memory was constant. Below are few details Cassandra is running with -Xms982M -Xmx982M -Xmn200M
-ea -XX:+UseThreadPriorities -XX:ThreadPriorityPolicy=42 -XX:+HeapDumpOnOutOfMemoryError -Xss256k -XX:StringTableSize=1000003 -XX:+AlwaysPreTouch -XX:-UseBiasedLocking -XX:+UseTLAB -XX:+ResizeTLAB -XX:+UseNUMA -XX:+PerfDisableSharedMem -Djava.net.preferIPv4Stack=true -XX:+UseParNewGC -XX:+UseConcMarkSweepGC -XX:+CMSParallelRemarkEnabled -XX:SurvivorRatio=8 -XX:MaxTenuringThreshold=1 -XX:CMSInitiatingOccupancyFraction=75 -XX:+UseCMSInitiatingOccupancyOnly -XX:CMSWaitDuration=10000 -XX:+CMSParallelInitialMarkEnabled -XX:+CMSEdenChunksRecordAlways -XX:+CMSClassUnloadingEnabled -XX:+PrintGCDetails -XX:+PrintGCDateStamps -XX:+PrintHeapAtGC -XX:+PrintTenuringDistribution -XX:+PrintGCApplicationStoppedTime -XX:+PrintPromotionFailure -XX:+UseGCLogFileRotation -XX:NumberOfGCLogFiles=10 -XX:GCLogFileSize=10M -Xms982M -Xmx982M -Xmn200M
After certain time We are receiving following OOM errors
ERROR [CompactionExecutor:4] 2020-08-12 10:58:50,289 CassandraDaemon.java:195 - Exception in thread Thread[CompactionExecutor:4,1,main] java.lang.OutOfMemoryError: Java heap space ERROR [CompactionExecutor:4] 2020-08-12 11:01:21,652 JVMStabilityInspector.java:118 - JVM state determined to be unstable. Exiting forcefully due to: java.lang.OutOfMemoryError: Java heap space
Please let me know what changes should we implement and what else is needed ?