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From Victor Kabdebon <victor.kabde...@gmail.com>
Subject Re: Abnormal memory consumption
Date Mon, 04 Apr 2011 18:05:19 GMT
And about the production 7Gb or RAM is sufficient ? Or 11 Gb is the minimum
?
Thank you for your inputs for the JVM I'll try to tune that


2011/4/4 Peter Schuller <peter.schuller@infidyne.com>

> > You can change VM settings and tweak things like memtable thresholds
> > and in-memory compaction limits to get it down and get away with a
> > smaller heap size, but honestly I don't recommend doing so unless
> > you're willing to spend some time getting that right and probably
> > repeating some of the work in the future with future versions of
> > Cassandra.
>
> That said, if you do want to do so to give it a try, I suggest (1)
> changing cassandra-env to remove all the GC stuff:
>
> VM_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="$JVM_OPTS -XX:+UseCMSInitiatingOccupancyOnly"
>
> And then setting a fixed heap size, and removing the manual fixation of new
> gen:
>
> JVM_OPTS="$JVM_OPTS -Xmn${HEAP_NEWSIZE}"
>
> Then maybe remove the initial heap size enforcement, but that might
> not help depending:
>
> JVM_OPTS="$JVM_OPTS -Xms${MAX_HEAP_SIZE}"
>
> And then go through cassandra.yaml and tune down all the various
> limitations. Less concurrent readers/writers, all the *_mb_* settings
> way down, and the RPC framing limitations.
>
> But let me re-iterate: I don't recommend running in any such
> configuration in production. But if you just want it running for
> testing/for just being available, with no special requirements, and
> not in production, the above might work. I haven't really tested it
> myself; there may be gotchas involved.
>
> --
> / Peter Schuller
>

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