I have a 16 node 6.3 cluster and two nodes from my cluster are giving me major headaches.
10.71.71.56 Up 58.19 GB 108271662202116783829255556910108067277 | ^ 10.71.71.61 Down 67.77 GB 123739042516704895804863493611552076888 v | 10.71.71.66 Up 43.51 GB 127605887595351923798765477786913079296 | ^ 10.71.71.59 Down 90.22 GB 139206422831293007780471430312996086499 v | 10.71.71.65 Up 22.97 GB 148873535527910577765226390751398592512 | ^ The symptoms I am seeing are nodes 61 and nodes 59 have huge 6 GB + commit log directories. They keep growing, along with memory usage, eventually the logs start showing GCInspection errors and then the nodes will go OOM INFO 14:20:01,296 Creating new commitlog segment /var/lib/cassandra/commitlog/CommitLog-1281378001296.log INFO 14:20:02,199 GC for ParNew: 327 ms, 57545496 reclaimed leaving 7955651792 used; max is 9773776896 INFO 14:20:03,201 GC for ParNew: 443 ms, 45124504 reclaimed leaving 8137412920 used; max is 9773776896 INFO 14:20:04,314 GC for ParNew: 438 ms, 54158832 reclaimed leaving 8310139720 used; max is 9773776896 INFO 14:20:05,547 GC for ParNew: 409 ms, 56888760 reclaimed leaving 8480136592 used; max is 9773776896 INFO 14:20:06,900 GC for ParNew: 441 ms, 58149704 reclaimed leaving 8648872520 used; max is 9773776896 INFO 14:20:08,904 GC for ParNew: 462 ms, 59185992 reclaimed leaving 8816581312 used; max is 9773776896 INFO 14:20:09,973 GC for ParNew: 460 ms, 57403840 reclaimed leaving 8986063136 used; max is 9773776896 INFO 14:20:11,976 GC for ParNew: 447 ms, 59814376 reclaimed leaving 9153134392 used; max is 9773776896 INFO 14:20:13,150 GC for ParNew: 441 ms, 61879728 reclaimed leaving 9318140296 used; max is 9773776896 java.lang.OutOfMemoryError: Java heap space Dumping heap to java_pid10913.hprof ... INFO 14:22:30,620 InetAddress /10.71.71.66 is now dead. INFO 14:22:30,621 InetAddress /10.71.71.65 is now dead. INFO 14:22:30,621 GC for ConcurrentMarkSweep: 44862 ms, 261200 reclaimed leaving 9334753480 used; max is 9773776896 INFO 14:22:30,621 InetAddress /10.71.71.64 is now dead. Heap dump file created [12730501093 bytes in 253.445 secs] ERROR 14:28:08,945 Uncaught exception in thread Thread[Thread-2288,5,main] java.lang.OutOfMemoryError: Java heap space at org.apache.cassandra.net.IncomingTcpConnection.run(IncomingTcpConnection.java:71) ERROR 14:28:08,948 Uncaught exception in thread Thread[Thread-2281,5,main] java.lang.OutOfMemoryError: Java heap space at org.apache.cassandra.net.IncomingTcpConnection.run(IncomingTcpConnection.java:71) INFO 14:28:09,017 GC for ConcurrentMarkSweep: 33737 ms, 85880 reclaimed leaving 9335215296 used; max is 9773776896 Does anyone have any ideas what is going on?