Anybody experience one Cassandra server locking up?

[Brian Frank Cooper]

Hi folks,

I have been loading a 6-server Cassandra cluster with 1KB records. After a few 
million inserts, the insert rate drops dramatically. After investigation, one 
of the Cassandra servers seems to be in a bad state, using 100% of one core on 
an 8-core machine, and 0% on the other cores. Inserts to this box have 
completely stopped, and the inserts to the other boxes have slowed way down 
(more than a factor of 10 slower.) A "kill" or "kill -3" to the bad java 
process does nothing; I have to use "kill -9" to stop it. Has anybody 
experienced anything like this?

Additional info:

The servers are 8 core, 8GB servers. I am running 64 bit java 1.6, and here are 
the JVM options:

# Arguments to pass to the JVM
JVM_OPTS=" \
        -ea \
        -Xdebug \
        -Xrunjdwp:transport=dt_socket,server=y,address=8888,suspend=n \
        -Xms128M \
        -Xmx6G \
        -XX:SurvivorRatio=8 \
        -XX:TargetSurvivorRatio=90 \
        -XX:+AggressiveOpts \
        -XX:+UseParNewGC \
        -XX:+UseConcMarkSweepGC \
        -XX:CMSInitiatingOccupancyFraction=1 \
        -XX:+CMSParallelRemarkEnabled \
        -XX:+HeapDumpOnOutOfMemoryError \
        -Dcom.sun.management.jmxremote.port=8080 \
        -Dcom.sun.management.jmxremote.ssl=false \
        -Dcom.sun.management.jmxremote.authenticate=false"

(standard options from the Cassandra distribution, except for the 6GB of heap 
space.)

Replication factor is 1 (this is just a test, not a production setup) and 
memtable size is set to 1GB.

Thanks...

brian