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From Joel Samuelsson <samuelsson.j...@gmail.com>
Subject Re: Reduce Cassandra GC
Date Mon, 17 Jun 2013 07:27:30 GMT
> If you are talking about 1.2.x then I also have memory problems on the
idle cluster: java memory constantly slow grows up to limit, then spend
long time for GC. I never seen such behaviour for  1.0.x and 1.1.x, where
on idle cluster java memory stay on the same value.

No I am running Cassandra 1.1.8.

> Can you paste you gc config?

I believe the relevant configs are these:
# GC tuning options
JVM_OPTS="$JVM_OPTS -XX:+UseParNewGC"
JVM_OPTS="$JVM_OPTS -XX:+UseConcMarkSweepGC"
JVM_OPTS="$JVM_OPTS -XX:+CMSParallelRemarkEnabled"
JVM_OPTS="$JVM_OPTS -XX:SurvivorRatio=8"
JVM_OPTS="$JVM_OPTS -XX:MaxTenuringThreshold=1"
JVM_OPTS="$JVM_OPTS -XX:CMSInitiatingOccupancyFraction=75"
JVM_OPTS="$JVM_OPTS -XX:+UseCMSInitiatingOccupancyOnly"

I haven't changed anything in the environment config up until now.

> Also can you take a heap dump at 2 diff points so that we can compare it?

I can't access the machine at all during the stop-the-world freezes. Was
that what you wanted me to try?

> Uncomment the followings in "cassandra-env.sh".
Done. Will post results as soon as I get a new stop-the-world gc.

> If you are unable to find a JIRA, file one

Unless this turns out to be a problem on my end, I will.

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